When 2 curtains come together and there either isn’t attachment to a post or enough attachment room on the post we can have the two curtains zip together. This being said we do recommend a “safety strap” on these curtains which keeps the downward tension where the two curtains meet. – Incases where vent side attachment shares the same attachment posts at curtain post Velcro can be utilized in order to attach the side of the vent. Each side of the vent will have Velcro on the inside while the curtains to the left and right will have the opposite side of the Velcro to allow the vent to attach to the curtain.