There are a number of possibilities.
Here is one, attached as example. You could just duplicate (tri) the timing loop to control your three outputs.
This solution can be improved : the stop button do not act immediately, and wait until the running tempo is terminated.
I have added, just for the fun, another way of inputting the timing values, using a string.
Additional comment : you are overusing attributes nodes. Except for specific cases (for example when you want to modify a front panel indicator/control from a sub-vi), use local variables instead.
CC
Chilly Charly (aka CC)