why not make it colour pipe automatic, without using any planner, If i build a water pipe (autocolor makes its magic) and 2-3 sec later it turns blue.
Get pipe imput, apply color and DONE.

The short answer is that it's rather complicated to do that, and it's much easier to just loop over the specific pipes selected by the planner tool. BUT you're not the first to ask, and I doubt you'll be the last, and I've been thinking of some ways I might be able to make it work. I can't make any promises or time commitments, but I'll let you know if I'm able to figure it out :)