This is a Wish bug for having a shortcut or layer-box menu for grouping selected layers. Currently what i do to group layers is create a group layer and then drag all the layers that i want to be in group under this newly created group layer. this is cumbersome process if you are having large number of layers. Now that we have the ability to select multiple layers, I wish we could have this feature as well. we can select several layers in the layer stack and then we can have them grouped with a shortcut or clicking a menu option ( group selected layers) Reproducible: Always
https://bugs.kde.org/show_bug.cgi?id=336843 this is a similar request I added your 'group layers' request to that similar bugs are grouped ,and there is less clutter for devs to find it.
*** This bug has been marked as a duplicate of bug 336843 ***