Dynamic Android Call Forwarding

I'm developing a mobile APP and I need to forward the incoming calls to different numbers based-on contact group. I divided my contacts into groups and each group has a different c

Solution 1:

This What I found. The answer is: We can't do call forwarding after call is received on our mobile Why: Because call forwarding is done by network provider not by your device.

Process: - first you request call forwarding from network provider by using: MMI code 21. - Network provider will register your request and change call forward setting in your device. - When new call network provider will forward it directly and nothing will come to your device. as shown in this diagram