Multiple Ring group / Multiple missed call

I wanted, on an incoming call, to have extension 101 and 102 ring then if no answer before two rings ring more extensions 103,104 etc…

My setup:
ring group A with 101 and 102 and a 8 second delay, if no answer then go to ring group B

Ring group B with extension 101, 102, 103, 104 etc… if no answer within 30s then go to voice mail.

inbound route to ring group A

It’s working great, however:

  • extension 101 & 102 will see two missed call instead of one.
  • you have to time properly the delay of ring group A to avoid a weird ring pattern on extensions 101 & 102 when switching to ring group B
  • it increases traffic by having to release the call then recreating it for the ring group A extensions

Is there a better way to do it?