'Hare and hound' explained please

Its just a scratch race, but a group of riders, usually seeded by category or points to be presumed slower, gets roughly half a lap head start.If they get caught by the other group then everyone just races together, if they don't then the other group looses out.

I take it you riding at Britghton?

thanks, that makes sense. it wasnt explained well the last time when I asked another rider. Im in Dublin, Ireland. we have a nice outdoor 460m track.