Group levels for viewing and export

When printing maps, each level is printed separately. I would like to be able to group some levels together so that they would be treated as one.
Only one image would be printed for the group.
When moving around with a token I would like to see the "roofs" of the rooms but still be able to see into all of the rooms from above if the levels are grouped together.
For example, levels (-1)-(-3) are grouped and I can see within all of the rooms in levels (-1)-(-3) as long as one of those levels is selected. Level -4 however is separate and I can only see the roof of this level unless I select this level.