Unfortunately, this is not possible; however, an alternative is to use the logical OR operator.
E.g.
/c/firma/adresar/(stitky='code:VIP' or stitky='code:DULEZITE').xml
Filtering Using Element Enumeration for Labels
Can you filter by a list of elements for tags in the URL (e.g. "tags in (1, 2, 3)")?
Written by Petr Pech