Create relations from multiple regions to another region

**Is your feature request related to a problem? Please describe.**
I have long documents containing several regions (named entities). Some regions have multiple regions connected to them, and these connections are created using relations. I am unable to select multiple regions at once and connect them to their corresponding region, as the "Create relation between regions"-button is grayed out when selecting more than one region. Instead I have to create each relation separately, demanding a lot of clicking.

**Describe the solution you'd like**
I would like to be able to select several regions at once (e.g., using "Ctrl") and then create a relation from all of them to another region.