Restrict the user access based on specific Contract/Project numbers

User access for Contracts —> Invoices should be based on the Project/ Contract number. Each user should have access to the 4 or 5 projects.We already have BU wise restriction for the users. User data restriction should be based on the list of projects provided by the business also. Now, User is able to see all the Contract invoices of his BU. Is this requirement possible to implement? Please provide any work around if available.

Thank you.