Why, and more importantly how would you macro that anyways? (Im using Autohotkey for a couple of things, but I'm a total noob at it).
If you have a Logitech mouse, in their newest mouse software suite you can assign keyboard macros to mouse buttons. I have the middle scrollwheel click function set to be an autorepeat Spacebar macro that ticks every 0.375 seconds, or thereabouts.
There is a similar feature of Microsoft keyboards, but when I attempted that, it didn't work with ME3MP but it did work with Cookie Clicker.
That said, I was attempting to use it from a non-standard key. Perhaps setting it from a standard key would have recognized?
Anyway, once you get it working, you pick up the pizza, run normally, then click your macro button half a second later, at which time you can let go of the Spacebar. Plot your path carefully because you will have an extremely high propensity to stick to all of the things.