Assign a pool of numbers to client

I have a pool of number from operator and want to assign it to client, how to doit in right way? At this moment I create dialpeers which says that numbers are reachable by specific gateway.

You are doing it right. We have no any hidden logic for client number, so in your case operator will be originator(customer in yeti terms) and client will act as termination side(vendor in yeti terms). So logic with dialpeers is right.