At what age should a child stop sleeping with their parents?
I have a hard time with that one, because we did not have a family bed, yet I know some people who have been very successful with it and they said the kids stopped themselves at around 4 or 5 when they wanted to sleep in their own rooms.
You are the adults and you are in charge, so if you want to stop I think you can tell them that at a certain day you will all be sleeping in your own beds, but assure them they will still be taken care of if they need you. Use a calendar to remind them of the day and how long you still have until that day.
If they come into your room to sleep, you must take them back to their own beds each time because you must be consistent with showing them what you want. If you can do that for a week every time, then that should do it, but if you cave even once, you must begin all over again, and each time it gets harder.