How to create a Drupal View with multiple CiviCRM relationships?
You can use the relationship section of a view for this. A relationship in a view is a relationship between entities don't confuse it with the relationship you have between contacts.

So you could set up a view relationship starting from contact a (the a side of the civicrm relationship), or from contact b (the b side of the civicrm relationship). This a link to the civicrm relationship entity. When you add this relationship to the view you can define which civicrm relationship type. 

The next step is to make a view relationship between the civicrm relationship entity and the contact. This relationship is called CiviCRM Contact, the Contact B, or CiviCRM Contact the Contact A. 

Then in the fields section of the view you can add fields based on the entity. You can then say for example I want to use display name of Contact B. 

If you are familiar with SQL. A view relationship could be described as a join.