Data sharing rules limit at 15

Data sharing rules limit at 15

I see on the Enterprise edition there is a limit of only 15 Data Sharing rules?  Is this correct and is it org wide or per user?

We use territories, but they only work on Accounts, Contacts & Potententials.  We need to give granular access to Inventory modules, i.e. Quotes, P.O. and Invoices and Cases to non-sales team members.  It seems the 15 rule limit is not practical.

Thanks