Ring Groups chain

Hello!
I have to create incoming chain from 3 Ring Groups (600,601,602).
Incoming call going to the RG 600 (3 phones: 1451,1452,1453)
If no answer -> go to the RG 601 (3 phones: 1454,1455,1456)
If no answer -> go to the RG 602 (2 phones, 1457,1450)
If no answer - loop -> go to the RG 600.
If I set Ring Time about 40 sec for every Ring Group, then 601 and 602 Ring Groups never rang.
If I set Ring Time about 10 sec for every Ring Group, then 601 will ring, but 602 rang time to time.
Is it possible to create those Ring Group chain or It should be another solution?

Asterisk has no concept of numbered ring groups. These will be the result of a custom dialplan, most likely one provided by an Asterisk GUI, in which case you should ask on a forum for that GUI. If not done by a GUI, you will need to provide the relevant part of the dialplan.

My guess would be that something upstream of Asterisk is timing out the unanswered call.