Well I suppose if they are supporting people who expect to be very similar pace then it wouldn't be a problem, but if either competitor has a problem then I guess it could cause issues......
From memory i met my support at Dyranut (40k top of first climb), Geilo (90k just before series of climbs), the top of the 3rd climb (110km) and the bottom of Immingfjell (145k). So there was a long time before each meet which gives some flexibility, but remember the support crew will need to eat & drink too.
Can't see it being an issue at all on the run until you get to zombie hill, because if you make the cutoff for black (i didn't) you will need your support crew at the top, but what if the other competitor is still at the bottom (it is a very steep narrow road).
At the end of the day, I'm sure you could manage, all the support crews help each other out anyway sharing food, drink, clothes or anything else that is needed.
