for mounts I make two mapped keys for master and slave. if they are the same mount it will be easy.

make a new mapped key, call it "mount master"
give it any hotkey you want
click "step 1" and right-click on "actions" and choose "keystroke actions >> new wow macro action"
choose target = window:current
key combonation = whatever you want (i choose the same as the hotkey)

macro generator

/cast Great Gray Kodo

that is it. whoever is the main lead character atm, this macro will work for them. do the same for slave character(s) but choose a different hotkey/key combonation and target = window:w/o current


now if you have different mounts for your characters, you will have to do advanced macros in the macro generator. everything is the same as mount master above except the macro command.

here is what I got for my priests

!if (character is not "slot 2") /cast Swift Green Hawkstrider
!if (character is not "slot 1") /cast Swift Pink Hawkstrider

so if the master has the green hawkstrider it will cast that, or if the master does not have the green hawkstrider it will cast the pink. you can do this for all characters

as for breaking follow, make sure you turn off the mouse repeater when playing. if you do not, all characters will run forward when you push move up etc.