On each user you would likely have to reconnect on each instance of baresip since user data isn't preserved between user profiles. Depending on the VoIP provider, you can do this but only your most recent SIP connection will actively recieve calls, the rest you could only check voicemail or make outgoing calls.

You mentioned numbers plural, so assuming you want different VoIP numbers per user this is very much possible and as I've described above, each user has unique user data per app.