Hi man, I don't know a way to use Realcomp for Andy's C4, however, there's a multiband compressor in Reaper called ReaXcomp.
You need to deactive1/3/4 bands and keep active only 2.
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Way better option is Fabfilter MB. Here's an example by Kohle(Aborted, Crematory, Powerwolf)
Hope it helps!