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Please help. There is a problem I have tried to resolve for some time now. I want to come up with a pattern where i have a table with advertisements on a web platform. These advertisements shall be owned either by individual users (accounts) or by an entity which represents a group of users (accounts) the members of which have permissions on the advertisement. There shall also be a manager of the advertisement. When the advertisement is owned by a group, the accounts dont matter and the info for the group shall be displayed. My problem is that I always come with anti patterns for this schema. Can you suggest me something? Your help will be highly appreciated.