Can not link attachment display to entity reference view display

Changing the description of my question (original below). Looks like an attachment display can only be attached to a master (or block, page,feed) displays but not to an entity reference display. See screenshots in comment 1 below.
Is this a bug or am I missing something?

---original question--
I have been struggling to create a view (with user relationship module).

I would like to have a view (table) with a list of users with whom current user has relationship. This is easy. To this view, I would like to add the current logged in user in the first row. So the view would look something like:

Row 1: Current user name
Row 2: Related user 1 name
Row 3: Related user 2 name
...

So basically I want the same fields but from entities that meet the filter criteria, but with one exception in the first row.
How can I achieve this? I would appreciate any help.