Still forward to Cell when Cell is busy - to get Cell VM


I have a customer who, like many others, operate an out of hours mobile (cell) phone. They unconditionally forward the call from the physical handset, to whichever phone is on call.

This all works fine until a second call comes in, when the mobile phone is already on a call. Then the forwarding doesn’t forward the call, it passes it to the extension VM. That’s the issue I’m trying to solve.

There are going to be a number of solutions to this, I can already think of two or three myself, follow me, queue the call etc. I was just wondering what the considered best option is.

By preference, I would rather avoid a time condition, such as switching the inbound route at, lets say 18:00, because they don’t necessarily work fixed hours.

At the moment the inbound route is straight to a ring group, with the ext. of the handset they use to forward to the out of hours mobile, being a member. The default of the ring group, if the call isn’t answered is to go to the voicemail of the ext. which is why they find a bunch of calls when they get back to the office.

They would like calls to continue to hit the mobile phone, so that the carrier VM will pick it up.

I appreciate your ideas, as ever.