I never use menus and I didn't find it when I searched the code but I guess it's there and I just didn't find it.
I still don't understand what you're asking for. If it's anything more than basic stuff then it's likely not in the default functionality of AMX Mod X. It sounds like you're asking for something quite unique (I'm only assuming because I can't understand your explanation/request).
None of the cvars used in the menu plugin are used by the team transfer code.