How to combine two contents of same type and display in views
There is a module for that, Views Merge Rows. From the project's description:


  Sometimes when you use relationships in views you get a number of rows
  with the same content in some of the fields. This results in a huge
  table (grid, list, etc.) that affects the usability of your view. The
  Views Merge Rows module provides a way to combine rows with the same
  content in the specified fields.


Keep in mind that there is a pretty straightforward guide to configure the module in the project's page that includes very descriptive screenshots.