[Mick Fagan]

Nige, the way I perceive it, is that if you are in two (or more) groups, then you would have to send a postcard to each member of each group.

I would also assume, one would have a different postcard picture for each group that you are in.

Perhaps this different picture for each group, could be a requirement of being in multiple groups in a round.

An alternate way, could be to restrict the rounds to a set number, say 30. When the set number is reached, all later starters would go into the next round, which doesn't get underway until the set maximum is reached.

I'm already printing postcards, for the next round!

Mick.