Followme modification - add "bounced from" message

We’re using Followme to bounce calls back to assistants when advisors don’t answer. We’d also like to display a custom message so the assistant knows where the call is bouncing from. I already have these bounces ringing distinctively via info text, but general display text isn’t so easily manipulated. These are Snom 370s with big XML displays.

One experiement that almost worked was adding extra identities to phones for each possible bounce source. That gave us the displayed message and distinctive ring, but I couldn’t get the BLF subscriptions to work since they’re tracking the primary extension.

Something else I considered was modifying the original incoming number. As in, prepend meaningful text to the outside number from within the followme code. The code and I blinked at each other and went our separate ways. This still seems like it might be the easiest way if I can figure it out.

Any ideas?