https://stash.reaper.fm/v/21556/saeq%...0sidechain.txt
should work the same, only difference is you run one eq at a time through whatever (external) compressor you want, even doing them in series (and wet/dry?) Any single-band compressor/expander should theoretically work, from ReaComp to Molot even? Even MCompressor which has custom curves. You determine the sidechain/limit the frequency range manually. You can probably even freeze halfway through if you want to run it through /that/ many effects. And obviously you inherit whatever goodies the compressor has, like RMS size and hopefully look-ahead?
I dunno if other EQs allow this via automation, this should be simpler to set up though?
Only catch is that it is a mono compressor, as in it compresses both channels equally. It actually only looks at the left channel so maybe you can get a further speed increase via routing tricks. A left/right/mid/side version is possible but it would halve the speed of the EQ