no, users can only be in one group, but can be users of multiple keys.
You will have to authenticate whenever you try to access encrypted content that's protected by a centrally managed key. There's no way around that.
OK thanks. can they browse the stick in regular explorer or do they have to use the .exe that is copied on to the stick?
I guess you are talking about EERM? If so, you can browse "the stick" with the normal explorer, but if they want to look at the encrypted part WITHOUT EEFF installed, then they will need to use the EXE.
the EXE is only for the case when EEFF is not installed.