GOIP-4 and balancing by minutes for 4 sim cards?

Question

Asterisk

I connected one goip-4
trunk to the server with freepbx 12, goip in server mode.
The option with 4 trunks for each SIM card does not take off, since incoming calls from all SIM cards except one stop coming.
Currently, calls via SIMs go in turn of outgoing calls, distributing channels with prefixes 1,2,3,4 for each SIM card.
Actually the question is how to set up uniform balancing on one trunk and different SIM cards?

Answer 1

There are many solutions. It is desirable to repair the trunks for outgoing calls.
An option, for example, before a meeting of a call, check which sims are free. From CDR for their prefixes you request their total billsec. Call via SIM card with the lowest total billsec