This is tricky as user who sends tx from his BW is already tracking a specific txid, so this new pushtype could be duplicate.
Also, if you spend your several UTXOs in one tx - you should NOT receive several pushes (but GC is not aware about your address clustering, it only receives subscriptions about separate addresses).
So maybe the solution should be - when you see spend tx from monitored address - wait a bit if there were no push about this exact txid, and if not - then send push.