Because torrents can be registered in more then one group it will be good to have ability to combine groups or calculate intersection of two groups.

E.g. I have group with music. Some torrents registered on one tracker and some on other. I can create separate groups for both groups but I trying to sort all this music and put sorted music into "sorted" group. Now I need to have 4 groups to only for music on two trackers! I have films, anime, ps1 games and a lot of other stuff. I need to create a lot of groups to handle all this stuff.

I propose to do next:
1. On mouse hover over group name show at right side two buttons ("+" for combine and "-" for intersection.
2. If user clicked on one of this symbols instead of group name -- calculate combine or intersection for active list and chosen group and hide opposite operation from hover menu.
3. If user clicked on group name -- show this group without any calculations.
4. Add ability to save views on groups as dynamic groups in separate folder or subfolder.