[TYPO3-ttnews] Select news belonging to several categories at once

[Laurent LAPORTE]

Hello,

How do I display a list of news belonging to both the current category 
and a given category (which I know the unique identifier UID)?

The current category is provided by the parameter cat[xyz] of the URL 
witch is found in the GETPar variable. But how to retrieve the value of 
this parameter in TypoScript and combine it with a logic AND with 
another category?

------- Thank you.