Did a little FCC search for Costco and here is what I found!
WQLL302 - This is a nationwide license for UHF frequencies that shows analog emissions. I know Norwalk is on one of the UHF channels, I just do not remember which one. They are using TYT radios also for the most part and maybe a few CP200D radios as mentioned.
WQMD311, WQMZ420, WQNC - These licenses have MANY control points and appear to be for mostly older VHF channels. (note Norwalk and Brookfield are under WQMZ420)
Hope this helps a little!!
Regards,
Dave520