This has been available in ADE XL since IC615 ISR12. In either the Data View assistant or the Variables and Parameters assistant, you can use the ctrl key in conjunction with the left mouse button to select multiple variables or parameters, and then on the Right Mouse button context menu pick "Group as parametric set" (see the picture attached).
You can also add or remove variables from an existing parametric set (the parametric sets are highlighted with a different colour).
You can have multiple parametric sets; within the parametric set the variables/parameters are swept together, but between groups they are swept orthogonally (i.e. every combination).