Connecting 4 loops to 1 zone on retrofit kit

I am planning to move my existing, wired system over to ring using retrofit kits. It has 26 loops and the resistors are all at the panel. I would like to simplify things down to 16 zones so that I will only need 2 retrofit kits. I've outlined below how I plan to do this -- is there any reason this won't work? Does anyone see any issues / concerns with doing this that I might have missed? Thanks in advance for your help and feedback! Marc * All entry doors would remain on a separate zone. * Multiple windows in the same room would be connected to a single zone. * Loops will be merged in series at the panel, with only 1 resistor for the entire loop. * No more than 4 loops would be merged into a single zone.