Running two boards from one power supply.

[AJB32690]

Okay, so I have this idea for a project. Its going to be secret at the moment, but first I need to know if it will even work. To save weight and space, I need to run two boards from the power source, as pictured here: (Please excuse crappy MSPaint drawing...)



Both boards will not be under load at the same time. The boards will act independently, only sharing the power. What I need to know is, will each board split the voltage (I.E. both boards getting 3.6V each.) or will one board get all 7.2V while in use. Or will I have to manually switch off one board and turn on the other? What I need to be able to do is control one board, and then switch to the other one only by switching the Tx. Both boards need to be on at all times.

Sorry if this seems a little confusing... I'm trying to do something that hasn't been done before, which leads to many questions...