Probably the easiest way would be to have a multistep key action where you advance the step by 1 for each key press. So basically you do the actions as you have lined out in each step.

Take a look at some of the is boxer documentation about attack groups, conditionals and macro key action(or something like that). You can basically do something like this(NB not complete nor correct but you get the idea)

if character is "paladin1" then
/cast Concentration Aura
/cast Aura Mastery
else if character is "paladin 2" then
/cast some other aura
else......

then in step 2 you copy paste and swap the sequence of the paladins, then repeat for all four steps.

You can probably do it with round robin and attack group too, using similar script functionality.

So basically you have the right idea yourself.