Easy/Effective Ways to Reverse an Open Position?

[Dave64]

I'm starting to look into effective ways of automatically reversing a position when a market goes against me in certain circumstances. As an example:

My rule has fired and I have a BACK bet matched at 4.0 with an offset but my selection starts to drift and I now want to be a layer. I'm looking to automatically invoke a LAY rule to switch my position possibly using using stored variables that take into account current price, current negative liability, etc or is there an easier solution (apart from not being a backer in the first instance! )?