Threesome

Threesome! A great puzzlegame that would be perfect as a mobile phone game. Three friends are stuck in a room. To get out/clear the level you need to get all of them to the red "bullseyes". The problem is, there's locked sliding doors blocking your path. But by having one friend standing on a coloured marker you will open a corresponding door of the same colour - so it's just a matter of figuring out who has to move first to where and in what order. Easy as pie. Or?