Joomla & Virtuemart - Google bug

I require a cost and time frame for fixing following bug:

Google is cross referencing the URLS / products it lists from the wrong site.

Require help on how to stop google from making this mistake.


Current site set up consists of the following:

- Joomla / VM website running JMS 2 Win.
- Over 100,000 Virtuemart Products shared from 1 database across 15 sites

Any questions please message me.

Thanks