all 3 of my kids share a room at the moment.. We only have 3 bedrooms and one room is the toy room.. none of the boys have ever been woken in the middle of the night by each other.

The only thing we have found is them waking each other up in the morning but thankfully soem very firm words with our eldest have stopped it for now.
we are moving our eldest in to his own room soon and just having the 2 youngest sharing like it was previously