How can i remove shared calendar links from 'Other calendars'

Yea you are thinking right you need to hack the XML file that contains the Navigation Pane details.This is the only way I know of to remove those entries is to hack the XML file that contains the Navigation Pane details.

It's named <profile>.xml where <profile> is the name of the Outlook profile. Of course that only will take effect when Outlook is started the next time and has to be done when Outlook isn't running.

You'd have to examine those files and hack the formats to know what to delete and where