Could you preface the names of those in the smaller 2 groups?
i.e. if you have mostly end-users and a smaller number of dealers and manufacturers, place an underscore _Bob Dealer for dealers and a hyphen -Acme for manufacturers (or whetever preferred characters). Then when producing A/R aged report, it is easy enough to select all _Names as they'll appear at the top of the list together. The _ or - are unobtrusive enough on invoices, etc... (better than prefacing with (M) and (D) for example.)

Could you preface the names of those in the smaller 2 groups?
i.e. if you have mostly end-users and a smaller number of dealers and manufacturers, place an underscore _Bob Dealer for dealers and a hyphen -Acme for manufacturers (or whetever preferred characters). Then when producing A/R aged report, it is easy enough to select all _Names as they'll appear at the top of the list together. The _ or - are unobtrusive enough on invoices, etc... (better than prefacing with (M) and (D) for example.)

That's already going to happen. We actually need three levels of AR analysis - one by product (yes, I know about inventory items), one by the client who receives the services and one by the provider of the service. We are like a broker - like insurance. John Smith buys house insurance and car insurance and we set him up with ABC Insurance. Mary Hacker buys car insurance through XYZ Underwriters and Susan Waynut buys car insurance from ABC. I need the AR by type of insurance, by John, Mary and Susan and also by the underwriter. So - looks like templates is the way to go.