Q. Is there an easy way to select a number of devices that are all connected?

A. You can progressively select a group of connected items (perhaps so you can move them to a separate part of the map) by alt-clicking (option-clicking on Macintosh). The first alt-click selects the leaf nodes, then next alt-click selects everything else that's connected to the selection. The next alt-click selects the leaf nodes again, etc. You can then drag the entire selection to a convenient location.