Hi Casper,
Greetings from ShpeHertz!!!
Apologies for late reply.
When player join a room with the desired property using joinRoomWithProperties API, currently there is no way to find which room property other player passed during the room Join.
But you can do implementation using privateChat API.
you can send privateChat to respective user as per your business logic so that other player can send the desirec properties while joining a room. Event you can ask the roomId by which player has joined so that you can join the same room.
let me know if it helps.
Thanks
Vishnu Garg