I'm 'resting' at the moment, but I regularly start people off running in lunch hours at work - from running 1 minute, walking 1 minute onwards. I usually do this twice a week and think of it as my 'recovery' run - then I do another two hill runs and one distance on my own, at my usual pace. I like running4rwanda's idea - maybe you could look at the slower runs this way, and the faster ones as speed sessions until you are all at a similar level. Personally, I would find it very demotivating to have someone run on ahead, jog on the spot and wait for me - but everyone's different, I guess.