You can assign more than one effect to a footpedal.  However you cannot assign more than one footpedal to any one effect. 

In your case, you might assign all four to one pedal:  Classic Distortion/echo initially turned on but then toggled over to Tube Distortion/Reverb when you hit the pedal.  If you want to control the pairs of effects independently then you must use two footpedals and hit both in successsion to make the flipover.