Hi, @Luca_Lattarini - I would suggest tracking all selected options when the form is submitted. Capturing the data in either a list-enabled prop or a listVar would make it so classifications (for breaking the data apart) wouldn't be necessary.
For example, either of the following approaches would let you report on "red," "yellow," and "blue" as individual line items:
s.prop1 = "red,yellow,blue";
// OR
s.list1 = "red,yellow,blue";