Choosing a set of items and another set of items for every selected item of the first list (HTML + jQuery)

I have a list of shows, with each show there are associated several seances.

I need to select a subset of shows. For every selected (that is being in this subset) show I need to select a subset of its seances, in order that I could be able to select the list of seances associated with the show.

The best solution I have come up is the following:

• display the list of shows as a <select multiple> widget (wrapped in a jquery.multiselect.min.js wrapper);
• at the right of it display a <select> widget with the list of all shows selected in the previous widget;
• at the right of the list of selected shows display (using dynamic loading list of seances with AJAX) a <select multiple> widget (wrapped in a jquery.multiselect.min.js wrapper) with the list of seances for the show selected in the previous widget.

I ask about what are alternatives to the above solution.