Hello,
Yes, no and maybe. What is it you want to know? You say you have three sites calling into one and the erlangs for every site, and you want to calculate the number of lines needed. Needed for what? Inbound on the one central site, outbound from the three sites? Putting Erlang aside do you have any other stats, such as percentage of utilization, busies? Do you have a problem you are trying to solve?