Hey,
You can make them sub-customers.
To make them sub-customers, go into their profile and on the bottom of Additional Info you will have a checkbox 'This customer is a sub-customer?' check that and it will let you choose a Customer to link to.
If you still needed to add the distributors you can also do this from the 'New Customer' screen by checking on 'Add Additional Info?' and you will see the same option in that section.
After linking them you can search the Customer and you will now get a list of their linked distributors as:
Customer:Distributor.
- Mortaza