Just make a macro on your char you don't want CTM on. /Console AutoInteract 0 to disable CTM if this is a single box toon.

For your multi-box groups set up keymap to toggle CTM on and off it is what I use for all my teams.

For mixed melee/ranged groups I have a key to toggle CTM on/off for the whole group. As well as Action Target group to handle CTM and IWT on the melee ATG.