Add plugin control per post

I want to use the Comments Subscribe Reloaded plugin but I need the ability to turn off that option on a per-post basis. The reason is I have an occasion contest that gives me a few hundred comments and I don’t want people to get notified everytime someone replies.

How can I add an option to turn this on/off per post? I can hack my way through it if I have a tutorial or some guide help on per-post control.

thanks.