hi! i have a 3cx and audiocodes mediant e1 gateway. everythings work ok, i can call to pstn and recieve calls from pstn. i need to add some external line usage restriction rules to my environment. by defalt when i call to pstn 3cx sends the call to audiocodes and it tooks the first free line out of 30 available in e1. i need to set rules that would allow some extensions to use only specific lines from the e1. what's the best way to do it?