Selective commit access for some code

I'm evaluating RTC for a project, and we have a perhaps-unusual
requirement that I'm struggling with how to implement.

The requirement is that while the whole team (which actually consists
of three sub-teams) should have read access to the entire project
source code, there is a "protected" subset which only one
of the three sub-teams should be able to change. The remainder of
the code should be fully accessible to the entire team.

This structure needs to be implemented across multiple streams, too.
We'll have a development "trunk" stream, with other streams
for client-specific work or other applications, but the same access
controls must apply. Also, we may incorporate additional teams that
should have access only to these client-specific streams, and they
should have no access at all to the "protected" code.

This code protection issue is contractually required, so it needs to
be fairly bulletproof.

Can I accomplish something like this? How would I go about it?

Please excuse me if my terminology is off. I'm new to RTC.

This precondition can be configured per component per stream. It is new
in RTC 2.0 and you can read more about it and such scenario at:
http://jazz.net/library/article/215#componentadvisor