Add column to visual that comes from other query, without filtering other query

[JoeCrozier]

Hello, I have this visual:

As you can see, the table in it has columns from several different data sources on the right.  Well, I'd like to add one more column.

My data source "Staff-Good" has information about the subjects that would be in this visual, it looks roughly like this:

 (obviously thats a fake snapshot from excel, but those column names, etc..

As you can see, this 'staff-good' has information about which staff members are assigned to what subjects.  Additionally, not pictured, I've already created a column in both 'rv_protocol_subject_basic' and 'staff-good' that is a mashup of the protocol no. and subject mrn.... to use as a key to merge the two tables.


In my original visual I'd like to add a column for "Data managers assigned to that subject".  I.e. if subject 12345678 is one of my subjects in my visual, and they have ten rows in the 'staff-good' data source for all of the staff assigned to him, I'd like to bring in the one row that has their data manager:

 and display their respective staff name on the visual:

I've thought about duplicating the staff data source, filtering it to data managers, and then merging that query into one of my others, but i'd like to avoid that approach if possible.  I already have a lot of data sources and keeping track of them all in my model view is getting complicated.  Is there another way?