Just label those 20 frames something and on(click) send the playhead to that label.
Are you using the same 20 frames each time? Might get repetitive, but if so, you can have a gotoAndStop(page); on the last frame of 20... where "page" is a variable that is on the web buttons.
So, each page has it's own label in the file like "aboutme", "portfolio" etc. On each button, let's say About me, you first have page="aboutme"; and then the gotoAndPlay("20frames"); and at the end of those 20 have the gotoAndStop(page);