Can a group of furniture be rotated about an X or Y axis?

In making a truss and bolts from boxes, triangles and cylinders, it was easier to build them in plan view (vertically) and then rotate them about a horizontal axis. Except I cannot find a tool for that in "modify furniture" where the furniture is a group of furniture. The rotate about z axis is available, though that rotate the vertical object around itself so it is still vertical.