Ability to block/free calendar periods by guest 'groups'?

Hi there,
We have many repeat guests and we are finding that for peak periods/prime dates, we would like to give them an opportunity or advantage in booking these dates. We find that many are missing out on booking during these times. Given we have a high repeat guest database, we wish to be able to 'free' the calendar for say, a 'guest group' so that guests tagged or in this group can book ahead of us freeing these dates others.
Don't know if I have made the above clear? Hope so!
Is there a way to do this or to think in an alternate way to achieve the same result?

We've recently added the ability to create a quote that blocks time, so if you have a particular set of guests that always book the same week every year you can create a quote and check the "Hold these dates so that other guests cannot book these dates while this quote is active" box and it will hold the dates until the quote expires.

We don't yet have a general feature that would let you block dates for multiple groups of guests and let one of them get it, though -- just a quote for a particular guest. We're working on the multiple groups case :-D