How To Emulate An ISPF Editor Feature in Vim

I know this dates me, but back in the day I used to exclude all lines in the ISPF editor using X9999 and then use 'find' to display (unexclude) lines that matched the find criteria. I have been trying to do the same thing with Vim by folding all lines and searching, but my search unfolds all lines. Is there a way to search folded lines and have only matching lines unfolded?