I am using Kamailio and have just setup everything and added two subscribers to the system. I would like to know if there is a way to send INVITE requests according to an extension variable, instead of using the subscriber's username. Thank you and have a great one.
If what you look for is more identities for the same user, then yes, it is possible. To be clear, by this I mean to have the possibility to call alice@sipdomain.com using also 1001@sipdomain.com or manager@sipdomain.com.
One way to do it is using alias_db module, which keeps a table with the association between aliases and the main SIP identity. The default kamailio.cfg has an option to enable such a feature, look for WITH_ALIASDB define.