Object state synchronisation

Hi, I just started working with PUN and I'm facing a problem right now that I'm not sure how to solve.

So, I have a lobby scene where players have to step on an object in order to flag it as ready. When all objects are ready, we start the game. The thing is, I don't know how to procede to flag that object as ready for every clients.

I first thought about giving those objects a photonView in order to call RPCs. But those RPCs would need to be buffered and you can step off that object to make it unready again. That would mean a lot a buffered RPCs if players decide to "play" with that.

Then I read about the custom properties and thought about saving every plateform's states in the room properties. But I read that those properties are update every 5 seconds, so if a player joins the lobby after someone has stepped on a plateform, he would have to wait 5 seconds before seeing it as "ready". Plus the fact that he could interact with it within those 5 seconds.

So I'm kinda lost right now, If anyone could explain to me how to deal with those kind of synchronisation (because I feel like it will happen a lot), It would help a lot.