In-game macros with targetexact is the way to go. Then using Variable Keystrokes to setup the keybiinds to use depending on who's your main at tne moment.

One in-game Follow macro can handle up to 7 characters; If you need more, just create a second Follow macro for the remainder of the charters. If your on Team, it should figure out which in-game macro to trigger. Follow Team1Char1 sends CTRL+F11 to everyone. Follow Team1Char2 would send ALT+F11 to everyoner. Follow Team2Char1, however, sends Ctrl+F12 to everone.

The two Follow macros on the action bars for F11 and F12 are identical, except the character names have changed.