So the vendor structure tends to follow the Java style package naming convention (reverse of the domain and then the package / area name) really just to avoid any namespacing conflicts.
I’m not sure what pillar and partner refers to in your example but the namespacing is flexible enough that you can definitely do this assuming that there’s good documentation for this. Wherever possible and practical you’ll want to often share entities across subdivisions and platforms (and often organisations) rather than making schemas specific to an individual platform so that may be something to take into account.
Sorry this was meant to say subdivision and platform. The mode of thinking is that we want global minimum standards for what certain entities look like. It is very likely that certain subdivision / platforms will want more strict definitions according to their own needs. We don’t want to prevent them from doing this but do want to keep some very basic central definition in place.