Place for HBT (and other) codes

During the collaboration meeting there was discussion where to put code for HBT. But I think we should create some standard to avoid similar issues in the future with other codes.
So my question is how we should group our codes:
by analysis like:
physics/femto/femto_framework1 or framework2 …
or maybe by PWG like:
physics/pwg3/femto/ frameworkA, B, C
should we also keep the same convention for example macros?

I think this is a more general question for the experts. I do not see working groups in physics. And I don’t see pwg’s directories at all. And of course, you can’t add anything inside the femto directory (mpdroot/physics/femto).