Not a problem. So the first step is create a mask within DT. I love its masking capabilities with drawn & parametric masks. @s7habo has some great videos on masking if you need help creating them.
Second on the export is enable store masks. This is only works for a couple export formats like tiff, xcf and openexr. As a warning at least for tiff files only the first 4 modules with masks are included in the export.
Then within Gimp you can open that exported file as layers selecting the main image and mask(s) you want. For the provided mask I just opened the mask and re-exported it to keep it small in size.