I've been using Matrix for quite a long time and yesterday I bought Playa because I thought that it can do what I need.
I have a channel "Movies" and a channel "People". I made a Matrix field for the People channel with the column "Names" because some people have alias names. I made a a Matrix field for "Movies" with the columns "Name" and "Role". Name is a Playa field and I thought it's possible to make a setting that I can chose that I can select from the "People" matrix name Field.
So what I need in publish for the movies is a field where I can select a person (entry) from the people channel and then one of this persons alias.
John Doe (this is a entry) - David (this is a alias) - Steven (this is a alias)