I do not believe that is possible in the upper "file explorer" view pane. it is designed to mimic the wndows exporer experience. the contains and BOM tabs below get you displays somewhat like what you are looking for.
It can't really be done. Coming from WPDM, its a bit of a letdown. The best you can do is sort by file type and just remember what is the top level assembly, or manually make a tree with folders. The open dialog in SOlidworks does have a filter to Top Level assembly option, which is semi helpful.
Well that sucks. Don't Like IT.
Thanks for the feedback.
Well, it had that option in the begining of EPDM. "Enable browsing in files with references" set per user or group when it was Conisio,it was removed in PDMWorks Enterprise 2008. i miss it too.
I still have a pic of it:
Log an enhancement to bring it back!
Today you need to use the Contains and Where Used tabs.