Castsequence with a reset modifier is not against the TOS. You are not automating anything. LIke the first keypress will start casting your lightning bolt on your main toon, and then the second keypress will start the cast on your remaining toons, you just have to make sure to time it so it is .6 seconds after because I think the grounding totem will absorb everything in the .5 second span of time when it gets hit. Warrior Spell Reflect 'buff' you get when you use it will reflect everything in a .5 second span so I think grounding would work the same way. Something like this? (i'm not a macro expert yet, seems doable though from all the examples out there)

/castsequence reset=x lightning bolt,,,

/castsequence reset=x ,lightning bolt,,

/castsequence reset=x ,lightning bolt,,

/castsequence reset=x ,lightning bolt,,