Possible to make a third party waves compressor sidechain?

I love my Api-2500 stereo compressor waves plugin and would love to make it sidechain. I have tried a few different approaches for making the plugin sidechain but I think i may have to accept that it is not possible? The vst object only allows me 14 parameters to manipulate which are the knobs for ratio, attack etc.

To make it sidechain it would have to be able to detect another tracks audio output in live and interpret that signal to trigger its threshold on its track. In other words whenever the signal its detecting reaches a certain decibel range that would trigger the compressor to compress its signal. Max for live plugins have the sidechaining/routing ability. But, I am wondering, is there more to programming sidechaining that i'm not realizing? Do i need to change more on the compressor than just its input? It would have realize another signal but not output or compress that signal, just recognize its fluctuations. There are M4L plugins that recognize envelopes.

Whats Max's capabilities with 3rd party plugins? Is Max only a host for VSTs? Can it break into the plugins and build functions outside of their regular parameters. I'm not skilled enough to know how to do that or to care enough to do it right now. Is Javascript the one that can hack?

For now all it seems is that through Max hosting this vst I could make different fx or ways to control the parameters of the compressor that are already meant to be changed, knobs, threshold, ratio, attack, release, etc.

Is this possible?