When creating more than 1 region during runtime there is no way to differentiate/detect which region you want to test for. You can't add a region to a list, because you get an error. Also there doesn't exist a block to call it when you need to. So my solution would be to have two more blocks.
- Name last created region to [text] (This allows you to name the region you just created)
- Region has name [text] (This allows you to call the region by name for detecting collision or for other uses.)