Default role assignments by group content type

I have a couple group content types that need to have different standard administrator privileges. In the assignable roles form (/admin/og/og_user_roles), each group content type is considered separately so it is possible to assign the administrator's role(s) as required for each group, but it must be done manually, one group at a time.
In the default role assignments part of the form, group content types are not distinguished, so it is not possible to have different user roles automatically assigned to group administrators based on the type of group.

So I'd like to propose that the default role assignment fieldset be split in the same way that the assignable roles fieldset is.