You can make all of your moves relative to a custom Feature that is taught on some known corner of the workcell. You can teach new Features by going to Installation->Features and then selecting Plane (a Point feature could also work but planes tend to be a bit more robust). When you go to a new workcell you would simply re-teach the Feature or directly edit it and all the resulting waypoints would snap to the new Feature. There are also UR+ products that have landmarks which will speed the process up and be more repeatable if needed: https://www.universal-robots.com/plus/products/?filters[]=94708&sort=relevance