Program Cell / Mobile To "Relay" Call To 3rd Phone

Hi all! n00b here... not sure which sub-forum this post belongs in. (1st post, pls excuse). When I was in the army, we (commo) we used to take field phones, switchboards, computers --- whatever --- and 'interface' them (hardware based hook-ups) and create 'patches'. That is, if caller A had a device (field phone) but target B did not, but had some other device we would route the call from A through a device exactly like o similar to target B's so B could get the call or message. We could also call from a HF (high freq: .5 Mhz -to-3 Mhz) radio to a telephone. So! Question is: How to go about programming today's average cell phone such that it 'relays' a call from a call originating phone, transposes it or 'piggy backs' the call such that the call is re-routed through the 2d (phone B in this case) and then passed through to the ultimate destination! Note: final destination (receiver C) would for all practical purposes only know/acknowledge a call from phone B, not phone A from which the call actually originated?? Can be done?? (any ham radio operator in your area will be able to fill you in; just tell 'em 'phone patch; i.e. phone-to-radio, etc). Have A Healthy, Prosperous Day!
---rob
---rob

Based on my limited experience, it seems one would need multiple pieces of external equipment to build an app like this.