/
      aaaaa               # Find me aaaaa
           (?:            # Followed by, but do not capture
            (?:           # Group but do not capture
                (?!       # Something which is not
                    aaaaa
                    .    #and any char including newline
                )
            )*             # As many as possible
        )
    /gs        # Repeat the match, dots can include newlines