Hi
There is a difference in "spread loss" and "distribute loss" trigger actions.
spread loss zeros the loss on the selection you are trading and moves a much higher liability to the other selections
distribute loss is the opposite of green up, it take the loss on the selection and distributes it evenly across all selections.
I think this is the one you are after, but please check the help file for descriptions of both actions
there is an example trigger
here which are three simple distribute loss triggers (stop loss) for laying. the trigger file on the website is for an earlier version of MFP, I have converted it for the current version and attached it to this post