Suppliers Associated To Vendors

The documentation is not clear. Every supplier need be associated with a vendor? Can I create a supplier that provide product to more than one vendor?

In the documentation there is not a field where is required to associate a vendor (, but in the latest version (4.12), seems to be impossible to create a supplier that is not associated with a vendor.

The necessity of associated a supplier to a vendor doesnt make sense to me. If I have a big service provider that provide product for several vendors will be necessary create the same supplier several times? One for each vendor?