Adding a component to glyphs of specific unicodes?

Hi, all of designers!
I’m making glyphs of Korean font!

As the specific of Korean alphabet,
the final components are repeated
for a constant interval of unicode.

For examples, 강(AC15), 갱(AC31), 걍(AC4D)…
have lower ㅇ, and the unicode interval is 21.

So, I wonder how I select the glyphs
like above screenshot.

If I can select Ac15, AC31, AC4D…,
then, I just pasted the components.

Or, if I have to use python script,
I will be pleased if you let me know that info!


Have you read this: