I agree go with the Automation F.ex. you can put the amount of feedback on the echo all down to zero and at the last part of the block raise it form one pattern to another worked for me on Liquid Clouds. If You don't know what I'm talking about let me know.
I think I know what you want to do here, but in order to do it you have to learn how to manipulate VST's in the Automation , here is a link to a tutorial I made.
At around 03:10 you can learn what I am talking about, so as I see it, you use the automation to turn up and down the gain or the volume in ohmicide at the right time in the song, I don't know if you can turn it off but you should be able to mute it this way, you can also make slow fade ins and fade outs this way.