Override unicode characters using fontconfig

[kocv59]

I can override a unicode character in kitty conf using symbol_map to tell it another font to use.

font_family Default Font
symbol_map U+ABCD Override Font

Is symbol_map a requirement to override a character or if I configure fontconfig to do the same thing I can remove symbol_map from kitty?

Anyone knows how to do that in fontconfig so if I'm using Default Font and want to display U+ABCD it uses Override Font for that?