drupal multisite breadcrumbs

So here is my issue. I have 70+ Drupal sites all set up in a multisite install. Each site is it’s own database.
All the sites share a common theme. The problem is I need to have breadcrumbs carry over from one site to another as the user clicks around. e.g. main site homepage > site one homepage > site one page > site one page 2 > site one page 3 > site one page 4(current page the user is on). At this point the user moves to the next site. I need the breadcrumbs to show main site homepage…site one page 2 > site one page 3 > site two page 1(current page the user is on). I would like to put this code in the template.php file and not have to use a module. Anyone have any idea how to make this happen? I need to have this done by the 24th of this month.

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