I would like to have calls to our number ring at several extensions at our premises and then ring my mobile number after around 3-4 rings in case I am not in the house. I have this set up as two Ring Groups, one that rings all the extensions, and then if there is no answer, it goes to a separate Ring Group that comprises just my mobile number. I find that calls that very often when I pick up on my mobile I cannot actually connect with the call for some reason; the phone says I'm connected but nothing is audible.

Is this the best way to set up the FreePBX system to accomplish this, or is there a better way?