Want to make a grooving plane. Do I need both left and right hand, or is there a different design I could just make one of?

I'm planning on making a plane for cutting 1/4" grooves that are 1/4" from the edge of my material. I'm seeing designs (e.g. in fine woodworker #219) where you make both a left and a right hand version- I assume this is so you can always go with the grain when cutting a groove. I'd rather not make two seperate planes and buy two plane irons- is there a simple-ish design I can use that could cut in either direction?