Essential r9.1.12. I have a configuration where there is one phone that takes all calls and the other people who answer calls all have bridged appearances for the "lines." The service is a PRI. They like it because it emulates their old system (I know, don't shoot me.) The issue is that one person wants to use twinning. If they twin their desk phone it will not ring their cell phone. If they dial their extension from another phone it will twin. Is this normal behavior?