I'm sure you've heard of an old fashioned country barn raising, so how about you use that theme to have a "swing raising" party. Invite friends and family members with kids and have a new kind of "raising". With enough people, it will take no time at all, and once you're done, while the kids are enjoying the play area, the larger kids (adults) can gather and enjoy themselves somewhere within eyesight (and earshot).
Your swing will be anchored, yes? I ask, because as kids get older, they start getting bolder and that lack of fear can cause stress on the swing.