Though it can be done, it's generally only recommended to do that briefly when testing (ex. running a VTZ as XPanel to emulate a TSW that's in another room, etc.), and not during actual deployment/runtime.
Crosstalk can particularly become a problem when you're using things like CRPCs and Smart Graphics applications (Media Player, etc.); less of a problem for a UI project only comprised of basic buttons/gauges/etc.
Dave H - Crestron True Blue Tech Support Engineer Since 2014