Many of our locks can be keyed alike as long as they are from the same manufacture and have the same security rating. The Yale Platinum range cannot be keyed alike. I would recommend the Asec Kite Elite - Euro Double Cylinder 50 - 45 (95mm) which is available in many sizes.

You need to remove the key from the inside in order to open from the outside with the Yale Platinum 3 Star cylinder. You may want to look at Asec Kite Elite - Euro Double Cylinder 35 - 35 (70mm) as an alternative.