I am trying to build a crm like database with some billing functionality. The way our client base is setup we could have a client that wants to be billed based on a group of client codes and others individually even if they have multiple client codes and still others that are represented only by one client code so they have no group. For those that have a group and use the group it isn't necessary to keep the client codes that are in the group because everything is based on the group. So I am trying to think if have a groups table with a group name and client code column, having nulls for those that don't have groups or have client codes and groups all in one table and have them represent a client and just accept duplicates for those that can be grouped for address and other information, but for billing aren't.
I don't know if that makes sense. Please ask questions to help me clarify. And I appreciate any thoughts you have.