Masking Invisible Walls

Is there any easier way to setup invisible walls for more complex landmasses like islands than setting up a million blocking volumes?

In my project, I have an island built from a landscape surrounded by a water mesh that I’d like to use as the level boundary. I’d have to use dozens of blocking volumes considering the island is far from being a quadrilateral.

ERROR : Collision not allowed deleted my barrier when importing Creative 1.0 map to UEFN. I dont know how to get an island collision/barrier/boundary around my island.