do it like this you'd better use good receivers that have a fail-safe. because when you transmit on a certain channel, there will be nothing on the other ones but interference. i'm not sure if it's a good solution if you don't want the "unused" ones to move by themselves. the risk is greater if the channels are close to each other.
using one stick for each is a solution, but of course you won't be able to control more than 2 units. 