First off, welcome.

Those cheap rc toys often use 27mhz or 40mhz. These systems come with a prefixed channel and might be the same. Transmitter A could very well be controlling receiver A and C that way.

Servo's can be picked up for under 4 pound a piece.

Why don't you try to convince them to build a true featherweight as a team.
This can be done for less than 200 pounds total.