What they're really asking for is multi-user accounts, which is a whole can of worms... also the address uniqueness requirement seems like it'll leak your custo

What they're really asking for is multi-user accounts, which is a whole can of worms... also the address uniqueness requirement seems like it'll leak your customers' information. Also don't understand why the system for spamming marketing emails needs to share the same address table (and associated headaches) as actual customers. Presumably you will want to spam people who aren't in the system yet...