Actually - it is possible. I thought I had the same problem, but if you move the references that turned up in your search into a new group, and then click back into the original group you searched in, you’ll see each of the references that were search results highlighted in light gray. If you right click the first one you see without left clicking, it will let you do “Remove references from Group”. It’s like all the references from your search were individually selected using Crtl+ … you just have to go back to the original group to make “Remove references from Group” an option.
Hope this helps!