using a lipo Rx pack to power Rx and servo in a flux?

[sharkattack99]

i have an airtronics mx-3 FG. can you use diffenct Rx with different radios, like a speckrium Rx and a airtronics radio? that sounds easier to a bec so just cut the red wire if i use on? and how do i set up the 7.4v to the servo? thanks.