i just do
/cast [target=paladin1,exists,nodead][target=paladin2,exists,nodead][target=paladin3,exists,nodead][target=paladin4,exists,nodead][target=castingpaladin] Cleanse

/cast [target=paladin2,exists,nodead][target=paladin3,exists,nodead][target=paladin4,exists,nodead][target=paladin1,exists,nodead][target=castingpaladin] Cleanse

/cast [target=paladin3,exists,nodead][target=paladin4,exists,nodead][target=paladin1,exists,nodead][target=paladin2,exists,nodead][target=castingpaladin] Cleanse

ect, seemed to work well. If i need to cleanse one specific target i click them on vuhdo and everyone cleanses that one target.