You probably don't want to use addons but I use smartbuff for these things. You can trigger it with a /click so all the characters will buff at the same time. So if you load the same paly's to the same slots they can be set to only buff might or kings.
I also remember in isboxer there is a "ischaractername xxxxx" or similar for the macros so you can set the slot to specify that character to cast that line. I used that one previously but don't use it right now.
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