My first thought is to Create a transform column and then give it a nice short name, and then use it as the X grouping column
Right click in the selection window on the X grouping column you want to use, and select Formula. Just click on OK. Then in the selection window, right click on the new transform column and select Rename, then change the name to the nice short name you want to use.
Finally, drag the new transform to the X Grouping drop area.
Jim