I am working on a call forwarding Android app. Call divert is working very well, but I need to implement call conferencing as well. If I am calling from my number to a second number, then the call should be divert to another number and all three participants should be in conference conference. I don't know how to do this.
You can't do this as of now. You can check this thread. However you can make conference call using VOIP.
These are some VOIP providers: