Then you just have to write the program for following the street symbols. The scheduler attends to the synchronisation at all. It ensures that the first Kara waits for the other one when it has entered the meeting room fields.
You could imagine a second solution, where the Kara pays attention for a tree besides the street. Then it would enter a state that is marked as barrier state. The disadvantage of that solution would be, that you have to integrate the synchronisation to your program, what would be much more complex that in the world.