I know there are individual trackers such as Strava and Endomondo but does anyone know if it’s possible to group users together to track a race? and analyse the group results afterwards?

I’m not sure it’s what you’re after, but http://www.opentracking.co.uk/ does stuff like that (disclaimer: a mate’s company I’ve done a bit of work for).

Yeah,, thats the sort of thing I’m looking for, but it’s just for a bit of fun on our rides out, so after something cheap (free).

Was hoping there may be some sort of feature in strava/endomondo where you can group users together.

The Flyby feature in Strava would do for that?

http://www.matesrace.co.uk/

Never used it but I believe this can do what you require.