.required_unless() or required_unless_one() on AppGroup

[AuroransSolis]

Pretty much what it says on the tin. Is there a way to get something like .required_unless() or required_unless_one() on an ArgGroup? I've been trying to figure out some way to make something like that happen for a while now, but it seems to me that at the moment it'll require validation external to App. The idea is that I'd like to require some group to be used unless some other argument/group is present.

[pksunkara]

I don't think there is. Could you please create an issue?