Technically it's fine, SAM won't crash if you do that and MySQL/MariaDB is more than capable of handling 2 database connections at the same time.
It will most likely not work to sync your 2 sites, though. The timing is too short for that. SAM only stores the queue, history and libray in the database. Not the current state of the players and it doesn't synchronize it's clock with the database or decide when to pick a new song based on the database time.
What will most likely happen is SAM #1 will pick song #1 from the queue and moments later SAM #2 will pick the next track because the other one is already gone from the queue. (If you keep a queue at all)
Abusing PAL to help is really hard. If you'd make SAM #2 pick the last played track from the history, it would probably work most of the time, but after a few days the time difference will likely drift in favor of either #2 staying too long behind (i.e. it would skip liners and other short tracks if it finishes the last track later by more than the shortest liner/ID/track in your library - i.e. 10 seconds after #1 when your liner is only 5 seconds)
All in All it's probably not worth the effort. If you want to decentralize your station, invest in separate streaming servers instead and supply the streaming servers with a bunch of fallback tracks to use when no encoder is connected.