Creating selectable "block" from selected group
Not exactly the answer you wanted (since Eagle does not support defined group) but here's a workaround I use.

I put that stuff on the tDocu or bDocu layer. Then I can temporarily turn of tPlace and other layers so I can select it easily by just dragging a box around it. This makes moving tables and other documentation easier.

The danger is forgetting to include tDocu and bDocu in the silkscreen when generating gerbers so I make sure to use my own CAM processing file where I've already included those layers.