Assigning multiple material properties to diffused interfaces

[MinMorsh]

I am using Voronoi tessellation (PolycrytalVoronoi) to create a 64 grain model (op_num = 20) in 3D and then assigning the electrical conductivities (bulk and interface) using bnds variable (BndsCalcAux). Here, when bnds>0.9, I am assigning bulk property and interfacial property to the rest.
Here is the Materials block of the current model that I have.

[Materials]
  [./ecCond] #The equation defining the electrical conductivity is defined here, using two ifs
      type = ParsedMaterial
      block = 0
      constant_names = 'length_scale k_b k_int'  # b = bulk, int = interface
      constant_expressions = '1 4.9758e-7 6.63e-5'
      function = 'sk_b:= length_scale*k_b; sk_int:= length_scale*k_int; if(bnds>0.90,sk_b,sk_int)'
      outputs = exodus
      property_name = ecC
      coupled_variables= 'bnds'
    [../]
[]

I need to assign multiple materials to the interface so that some part of the interface should have one type of interfacial material (less conductive, denoted as sk_int1), and other part of the interface should have another type (more conductive, denoted as sk_int2). Any idea how to achieve that?

[GiudGiud]

so that some part of the interface has one type of interfacial material (less conductive, denoted as sk_int1), and other part of the interface has another type (more conductive, denoted as sk_int2).

how is the interface defined? Is it a sideset in the mesh? Is it a subdomain?
Is there a criterion already for selecting between the types?

[MinMorsh]

That's what I am looking for here. Can I make separate subdomains of the interfaces so that I can assign different properties to them?

[GiudGiud]

if the mesh is fine enough to resolve them, sure. You can use this object to modify the subdomains based on a variable value:

https://mooseframework.inl.gov/source/meshmodifiers/CoupledVarThresholdElementSubdomainModifier.html

[MinMorsh]

I have been using similar technique here function = 'sk_b:= length_scale*k_b; sk_int:= length_scale*k_int; if(bnds>0.90,sk_b,sk_int)' (using if statement) to assign properties to grains and interfaces. Now I am looking for something that will enable me to assign multiple properties to the interfaces/GBs (illustrated below).

[MinMorsh]

Yes, the mesh is quite refined at the interfaces. Below is the current mesh I am using, generated with Adaptive Mesh Refinement (AMR).

[GiudGiud]

If length scale is enough to describe the interfaces then your approach works?

You can change all the properties using such if statement, one by one.

Length scale could also be used with object I mentioned to create a new subdomain, and use new Materials that are block restricted to this new subdomain