Right now there is a workaround. It requires a little investement. Guys - get yourself DDMF Metaplugin. It comes with additional vsts: "send it" and "receive it". You put "send it vst" on your for example kick track. and you put metapluginvst on bus you want to duck. Inside metaplugin you put 'receive vst' and a compressor of your choice. Then inside metaplugin route main signal to the compressor and signal from 'receive' to sidechain input of the compressor. It is really easy to set up, but of course requires some work.