The GTalk and Hangouts appear to be two entirely different things. Once I switched over to Hangouts, folks subscribed to my presence information no longer saw m

The GTalk and Hangouts appear to be two entirely different things. Once I switched over to Hangouts, folks subscribed to my presence information no longer saw me online, and from within GMail I have no way of messaging them without switching back to GTalk Mode. On Android I don't even have a way to switch back.