I bought the kids a fun hammock that they could share.  It is wrap around material so they would not fall out and I put it near their playhouse about a foot off the ground.  Naturally, they both wiggled and fought each other in the hammock which necessitated me buying a second hammock.  Now they both have their own and can hold hands and swing each other but have their own space.

They finished off the afternoon by going and getting their own snack from inside and then getting their own table to eat it at.