Feature: Separate custom room notification

A thing I'm missing in Android-Riot is notification customisability.
In that app it's possible to choose more generic notification settings, such as when my username is mentioned, when a message is sent to a room I'm a member of, etc.

What I'd _also_ like to have is a way of customising what sound a room makes that matches any of those notification rules. This way I'll be able, by noise alone, to discern what/who wants to reach me.
It would also be useful to have the generic rules customised per room, instead of the much more global context that's applied in Android-Riot.