Can you hide System Variables from the "VARIABLES" tab in Frame 10?

I'm currently working in a document, using several different user-created variables, and I'd like to know if I can hide the stock, system variables from the display, as I don't use them.  My reasoning is two-fold:

1. I just want to minimize the overall list to make for easier navigation
2. The "Sort" on Name functionality (ascending/descending) in the VARIABLES tab, doesn't fully work every time (i.e., sometimes the results are actually mixed up).

Any help would be appreciated.

Regards,

- Chris