That would be part of the multi-account option I have on Pokey's roadmap.

Bevause Pokey only requires a pubkey, you will be able yo register as many accounts as you want and configure the kind of notes you want to get notified. (A notification of your own posts is just trivial)

About the relay problem, you are right, but a similar approach as the one used for the outbox model might help to mitigate the problem.