For the record, I don’t use hammocks so this may be a terrible idea.
Could you get away with anchoring each hammock to the opposite side of a large diameter tree? Looking at the spreader bars it looks like they are trying to seperate the anchor points by 18-24” inches. A lot of trees in my AO are that size of larger. I am thinking that you could tie a couple of loops in a strap, tie them twenty inches apart and the tighten the strap around the tree so that it is tight. Then hand your hammocks form the loops on the strap. Using a loop in the strap ensures that your anchor point doesn’t slide along the strap.
Same idea could be applied to two trees that are close together. Might want to loop each tree in the strap to ensure that you can keep the strap snug if the tree sways at all in the wind.
Again, this may be a terrible idea.
2Hut8