GUIDE: Click Healing System Using Party Frames

[Apatheist]

I'm not entirely sure what you're asking. A Repeater Region repeats the actions from the current window to other specified window(s).
And if you're using the 'system' from this particular guide, I'm not sure just how you are trying to use it for several characters (as in theory it wouldn't work for multiple healers without changing things around).

It works fine for multiple healers, just not the primary window. When you configure repeater, it doesn't have the option to pass clicks to "all w/ current". It's not really a big deal though, it's just as easy for me to target the person and use a basic assist key with my healing.

[chazz]

It works fine for multiple healers, just not the primary window. When you configure repeater, it doesn't have the option to pass clicks to "all w/ current". It's not really a big deal though, it's just as easy for me to target the person and use a basic assist key with my healing.

If multiple healers are working fine for you then you are probably doing something different than what this guide describes, since this guide has the Lead character block off his/her Party Frame with a Click Bar (so if you were sending mouse clicks to the Lead from a Slave the Lead wouldn't be able to aquire a target).
Also I'm still not sure what you mean by "all w/ current" for the Repeater Region, since a Repeater Region sends whatever mouse input that happens within the region on the current window to the other windows. Meaning it doesn't function like a Mapped Key/Action where "all others" only sends the key to the other windows but not the current one.

EDIT:
I should clarify that I assumed, due to how you worded the beginning of the following sentence; "When I run 3 Sages, whichever window I'm currently on..."
That you mean that you are trying to be able to heal from all three characters.
Of course this guide would work for multiple healers, as long as you're 'controlling' them from the same character. Otherwise you would run into the problem with the Click Bar blocking off the Party Frames as I described above.
Getting it to work for all characters is however probably possible and something you might already have done, seeing as how you said it worked fine, but it would require doing things differently than what this guide describes (not using the Party Frame for targeting for example).