You should have no problem getting out of one. I don't think they can make you serve twice within a 6 month period, or at least that's the way it is in Texas. Does the summons have a list of waivers, etc? I would go on the first date, and then send the 2nd one back with the exception, or even take them both on the first date, and they could probably take off the list there for the 2nd date.