Hi,
I'm not sure how you would do this in playmaker without rigid bodies, but the easiest way would be to set up various collision events on each square with tags checking for each corresponding colour...
So, each colour square would be tagged with their own colour... Red with a 'red' tag, and so on...
Then when the red square hits the blue square, the collision event on the red square that checks for the 'blue' tag will be fired, go to the next state and do whatever you need it to!
You might have to be careful about doubling up using this technique though... because if you have the same collision events on the blue square, then a corresponding 'red hit collision' is going to happen on that too...
Hope this helps!