At long last, I’ve found the elusive preference settings in teleport for controlling the switching behavior. Previously in the normal settings tab, these options are now available on a per-host basis and only revealed when mousing over the external hosts in the layout pane.
See the extremely handy preference for limiting the switching by requiring that the Option key be held down.
Teleport lets you use a single mouse and keyboard to control several Macs. When enabled, you move the cursor to the edge of the screen and the mouse “teleports” to a nearby Mac. After teleportation, this mac is controlled by the same keyboard and mouse. As a bonus, the clipboard can be synchronized and you can drag & drop files between the two Macs.