We have a scenario where one contact record can work for multiple customers. In NAV, it seems that a Person type contact can only be linked to a customer through a Company type contact at one time. 

For Example, a contact John Doe, No. CONT0001 can only be linked to Customer CUST001 or CUST002 at one given time. Is there any way to link CONT0001 to CUST001 and CUST002 at same time without any customization?