[SOLVED] favicon- can i put in folder outside of theme files?

I am sorry if this has been asked before, but i cannot seem to find the solution...

I run several sites with Atahualpa on the same host... each time i upgrade Atahualpa, i need to re-upload the favicon (and other site images). I have not set up multisite..

what i want is to store my favicon in a 'global' folder. eg. http://www.mysitename/global/icon.ico.

This does not work when i place the full url in the favicon address box.. is this possible to do with out messing around with the theme php files?

I need the site(s) to be easily updated by other people.

thank you.
ortixia