Is it possible to link three modules?

I have a module entitled "Cost Impacts." Cost impacts are funds secured from a customer for work completed outside the normal scope of work.

IN the Cost Impacts Module, I have a lookup field linking the Cost Impact ID to the Deal in the Deals Module. That Deal is associated with a Customer from the Customer Module. How Can I create another link inside the Cost Impacts module but for Account? The goal would be that the Account Lookup autofill's based on the Deal lookup (each Deal is associated with only one account). Furthermore, I would want the Cost Impact's to show as a related list under both the Deals Module and the Accounts Module.

Thanks