Creating Custom Shelf (python) & Sharing over Network



I have the following issue.
I am trying to find a better way to share custom maya shelves throughout the company.

This is my approach so far:

I have a .bat file which points maya to all the relevant directories on startup and runs a mel script from the command line which executes python code which generates the custom shelf.

That part works all fine but when maya is closed it automatically saves the custom shelf in \prefs\shelves as a .mel file (as intended). So now if you open maya with the standard .exe the shelf will be visible.

However i only want the custom shelf to be visible when you launch maya with the .bat. How can i force maya not to save the shelf on exit?

PS: The reason i want the shelf to be newly generated every time maya is launched is to insure the shelf is always up to date and working with any version of maya.

any help appreciated!