Mapping two things to the one control

Hey is it possible to map two functions to the one midi control?  For example I'd love to be able to map the lighting channel to the crossfader I use to also change the Video channel.  

As far as I understand it seems to come up with a message saying this is already assigned so there's no way to make one button / fader / knob cover a few different functions.  I know you can do this in competitors software so is it something that will be considered?

Cheers so much