Yes that’s commonly how that’s done. There is no built-in function to change the class of all players in the island, but you would use Verse or another device to get instigation for everyone. A common device you can use is a Player Counter:
- Connect a button to the Player Counter’s “Transmit For All Counted Players”
- Connect “When Player Counted Transmit On” to the Class Selector
Make sure you change “Transmit For Player Counted/Removed” to “Signal Only”