At the moment, there is not a way to do it automatically, though another user has
requested some similar functionality that is being considered to solve this particular problem. It will involve users bidding offspec and/or main, though I haven't quite decided yet how to best implement it.
The tough part is making it easy to use, but flexible, and I've actually had users cancel before because their users couldn't figure out "!bid" and insisted on typing "bid."
But given the new dual specs, I'll likely be attempting to slide this functionality in the new version.
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It's all in the reflexes.