tracks. look at triple sliding closet doors

You can order doors for closet at my company :)

You can do 3 doors on 2 tracks, most common solution and you will have access only to 1/3 of closet opening or 3 panels on 3 tracks and you will have access to 2/3 of closet opening.

Search for sliding doors hardware (for example Jonson hardware works good for DIY projects), it could be double tracks and single tracks. Use double track for solution where you will have acces for 1/3 of opening and double+single track for solution where each panel suspended on its own track.