Adding explanation on migrating grouped account

user/migrate/open-source-repository-migration.md

@@ -10,6 +10,7 @@ This document explains how to migrate your repositories, and answers some common
 
 > Hi there! If you'd like to become a beta tester, please sign in at [travis-ci.org] and in [your account page](https://travis-ci.org/account/repositories), sign up to migrate your Open Source repositories.
 
+
 ## What information will be transferred to travis-ci.com?
 
 When a repository is migrated, the following information will be transferred to travis-ci.com:
@@ -61,6 +62,12 @@ Yes, you can select as many repositories in the Migrate tab as you'd like to mig
 
 We'll enqueue these build requests and the builds will be created in travis-ci.com as soon as the migration finishes.
 
+## Does the migration require any changes in our `.travis.yml`?
+
+No. Unless there was something very customised in your `.travis.yml`, no changes are required. 
+
+> Please note: the experimental IBM Power CPU queue is not available on .com, one can use `arch: ppc64le` tag on travis-ci.com, which will run your [IBM build in LXD container](/user/multi-cpu-architectures/).
+
 ## Migrating a repository
 
 ### GitHub Apps initial setup
@@ -128,6 +135,48 @@ Since the repository in travis-ci.org is now in read-only mode, the settings pag
 
 ![Locked settings page in travis-ci.org](/user/images/oss-migration/locked-settings-org.png)
 
+## Migrating within a `Grouped Account`
+
+> Please note: Grouping accounts was very rarely done, set only manually by Travis CI staff and was subject to assesment every time. This section concerns only a handful of accounts in Travis CI as only couple of tens accounts was set that way in the past.
+
+If you happen to have your account grouped with other accounts by Travis CI staff in the past in so called 'grouped account' setup, migrating your repositories from travis-ci.org to travis-ci.com and preserving this unique configuration requires Travis CI staff support.
+
+
+### How do I recognize I am part grouped account?
+
+* At least 2 Version Control System (VCS) accounts utilize common concurrency pool, e.g. two concurrent GitHub accounts utilize common concurrency pool
+* Your total available concurrency exceeds standard number of concurrent jobs for free builds available for single account
+* Optionally: someone in your team can confirm that you are part of specific customised grouped account configuration in Travis CI
+
+All of above must be satisfied at the same time. If you only notice increased concurrency limit, that may be a subject to separate configuration and you are welcomed to contact with [our support team](/user/migrate/open-source-repository-migration#support-and-feedback) to clarify details before you migrate your repositories.
+
+### How do I progress with the migration?
+
+If your account is a part of grouped account and you will migrate just repositories on single account, you will loose access to combined concurrency pool. Therefore all accounts must migrate their repositories to travis-ci.com and once it's done, Travis CI Staff can re-create configuration for you in travis-ci.com. 
+
+Whole migration can be done in seconds. Re-creating grouped account configuration on travis-ci.com should be completed within a couple of hours, depending on Travis CI staff workload.
+
+Following steps are meant to clarify the process:
+
+#### Preparing
+
+Organize & let us know ahead!
+
+* Reach out in your collaborative group and establish, when you want to migrate repositories to travis-ci.com; make sure all partaking account owners express their consent for the move and can inform contributors on the plan to migrate to travis-ci.com
+* Report to Travis CI Support team in order to confirm you are a part of `Grouped Account` on travis-ci.org, at best providing list of other partakers and up to date contacts to decision makers (and a GitHub ticket, if you have opened one on your account for that action) - contact via our Slack #embassy channel or [email address](/user/migrate/open-source-repository-migration#support-and-feedback), we will internally create a ticket for that request and follow it
+* Travis CI support will verify configuration (which accounts do belong to the group) and unless it's been already done by you - reach out to partaking account owners to confirm that migration of repositories for every partaking account is executed or planned to execute
+
+
+#### Migrating and re-creating configuration
+
+* Every account partaking in `Grouped Account` configuration must migrate their repositories to travis-ci.com following [migration steps](/user/migrate/open-source-repository-migration#migrating-a-repository)
+    * At least one repository migrated to travis-ci.com is required, however given you will need use the travis-ci.com app it's usually convenient to move all repositories at once
+* Once all partaking accounts have migrated their repositories to travis-ci.com, **reach out to Travis CI Staff** confirming readiness to re-create configuration on travis-ci.com (all partaking accounts migrated their repositories)
+* Travis CI Staff re-creates your `Grouped Accounts` configuration and answers on the request
+
+The whole process can be wrapped up within a couple of hours.
+
+
 ## Support and feedback
 
 If you have any further questions or comments on our Beta migration process or need help, please let us know at [support@travis-ci.com](mailto:support@travis-ci.com?subject=Migration%20Beta%20Testing%20Feedback). We have a dedicated team working on this project that will be glad to assist you.