In the past we've found that this doesn't work from the Crestron interface side of things. At least not at the outset of their partnership. From then, we've pretty much stuck to using ONE Port (source) to a distribution amp to get audio wherever it is wanted, and that worked well since grouping/synching issues sort of can't happen.

Is this still an OK way to do it, or can you group Sonos zones from outside of the actual Sonos app?