Donít know if this would work butÖ.maybe take a cushion to a boat or canvas shop and see if they can sew a length of material to the back side with a metal snap. There must be a place where you can drill the other half of the snap to. Either a frame or somewhere.
Guessing two straps per cushion. Each strap about an inch in width by whatever length you would need to reach your connecting point.
Our boat cushions worked the same way. The big difference is the material. You would want them to spread the connecting point out so you donít tear the Ultra Leather.
Tom & Bev, Riley 6yo Lab
2014 Entegra Aspire 44b, 2017 Jeep JKU