If I understand you correctly, you can inactivate a load. But how do you get the program to understand when to do so? I want the pressure load to be zero when two parts collide...
Hmm...if I understand you correctly, you have several steps in your analysis and wish to inactivate a load when you have reached a certain step (collision of parts), is that correct?
If it's true, what you have to do is go to the model tree, right click 'Loads' and select 'Manager'. The Load Manager window will pop up and you can edit the loads as you wish. Basically you can activate, de-activate and even shift loads between steps.
Oh, when you are done modifying the loads, jusk click dismiss to get rid of the window.