First I want to say that your forum is awesome and I realy love it.
I know that in solidedge it's possible to create "premate" (like mate reference).
I want to predifined the washer so when I will add it to the assembly, solid works will ask me to which face I want to coincidant the washer's face or which face i want to concentric the washer with the other part.
For example (in solidedge):
If I add a washer to an assembly, it asks to which hole I want to concentric the washer (which was predifined)
How do I do it in solidworks???