Hi Clare. We need this as well. Not possible today in the OOTB contents definition interface. We'd love if each Investment Type's filtering capability had at least the capability of their Object based power filtering. Example: Project power filtering would have the Team sub-object you're looking for.
Please vote up Enhanced Filtering Capability for Portfolio Contents Definition when you have a chance.
FYI - it's possible to run these 'Team Object' business rules in SQL/Gel and Xog the investments into the portfolio as a process that runs after a sync. I have this on my 'to do' list/spike backlog but haven't had the time to build it. This is heating up here for us again so I'll keep you posted if I get to this. If your organization throws development resources at this anytime soon I'd be most grateful to be kept in the loop.
What we all really need though is CA to Enhance Filtering Capability for Portfolio Contents Definition so there's no custom code or processes required!