[pmwiki-users] show menu to user group?

[SteP]

In my sidebar I need to show a menu entry only to users who have 
authenticated as part of AuthUser group @teamA.
What is the conditional markup for that?
(:if authid :)    no, that's eveyone, not just someone in @teamA
(:if equal $AuthId ? :)   no, I don't know who belongs to @teamA
(:if ??? @teamA :)

Thanks
--SteP