Share Database between multiple installations

Hello,

I have installed GD on Site1 and that will be the primary site. I also want to install GD on Site2, but use Site1’s Database. The reason for this is site2 is really just a subset of the site defined by a custom field (BizGroup). Is this possible and when I load GD on Site2, can I limit the data shown using the custom field (BizGroup=thisgroupname)?

I hope this makes sense, and more importantly, can be done easily

Thank you