Our 3CX IPPBX is connected to 3 SIP Trunk accounts (12 lines total). All incoming calls come through one trunk (6 lines) and the other two trunks are used for overflow and backup for outgoing calls. I would like to set up a rule that detects when the first trunk is nearly or completely occupied and then hands off the incoming call to one of our "backup" trunks. The intent is to free up one of the lines on the first trunk so that incoming calls do not get a busy signal. Can anyone tell me if this is possible and point me in the right direction?