MediaGroup: Don't include external media
Fix #344 (closed)
This is a naive approach to #344 (closed). It might be worth considering removing external media from groups altogether, but if we wan't those media to reappear in the groups in which they belonged if the parent entry point gets re-inserted, then we have to keep the relation between external media & media group, and filter out the results.
Edited by Hugo Beauzée-Luyssen