Multiple value for one custom variable


I’ve got a website divided in multiple categories. Each category contains news, events, etc. Each news/event can belong to multiple categories.
I’ve seen it’s possible to do this :

piwikTracker.setCustomVariable (1, ‘Category’, ‘Sports’, ‘page’);
piwikTracker.setCustomVariable (2, ‘Category’, ‘Europe’, ‘page’);

But considering at the moment I’ve already got 6 categories and I need other custom variables, that solution doesn’t fit.

What I’d like to do is the following :
piwikTracker.setCustomVariable (1, ‘Category’, ‘Sports,Europe’, ‘page’);

But I don’t know if it’s possible and if it is it involves extra code from me to display it correctly in the admin.

What are my options?

One way you can do this is to combine, so I would do:

piwikTracker.setCustomVariable (1, "Category","Region = $area"+ "| topic = $content", "page");

where variable $area can be Europe and Topic will be variable $content