Accessible cases for current user

Hi guys,

I am struggling to show specific cases for current user.  It means the user has to see only cases where  one of the contacts of the case's customer is current user or primary contact of the customer is current user.

Let say we've got a  case "Case1" that has "Test" customer, the customer has 1 to many relationship with contacts. One of the contacts has to be a current user.

I'm not sure if there is a way to write a fetchxml somewhere to restrict the cases?

Thank you very much for any help.