1 Parent table 1 Child table; 2 related fields

I have a parent table {Projects} and a child table {Clients}, and our company has found the need to create and link 2 fields of clients.  One is the Product Manufacturer, and the other is the Bill To Client.  Both are values stored in the Clients table.  I want to create 2 relations so that when a client is removed from the database, then both fields in the project are automatically set null, but I can not.  I keep getting 'possible cyclic redundancy errors' whenever I attempt to save these 2 relations.  I can create 1 but not 2.  Does anybody know what to do here?
jvj
Jamie V Johnson CAD Manager/Database Developer
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