5.1/quad to stereo send routing question...

Routing Question (N6):
I’m trying to set up a Quad channel with sends, so that the front L-R will send to a bus/group (let’s called it 1-2) and the rear L-R will send to bus 3-4.
That way I can use the Anymix panner to smoothly pan between front and back, and apply different fx to those two busses.
I haven’t done this for a while and remember it being a doddle in the old mixer. But for some reason I can’t figure it out on N6…helpie?