[Standards] Re: XEP-0163 (Personal Eventing Protocol) Allow multiple publishers; XEP-0045 (Multi-User Chat) Allow PEP

This isn't a standards/spec issue, but simple a lack of any existing implementation. We know how to have a PubSub service be on any arbitrary JID (that is one of the few parts of actual PEP still remaining in the wild) but servers haven't happened to implement this against JIDs that happen to be MUCs also.