Islam (mostly Sunni, with a Bektashi minority) is the predominant religion in Kosovo but hasn't saturated the Kosovar society, which remains largely secular.
About three percent of ethnic Albanians in Kosovo remain Roman Catholic despite centuries of the Ottoman rule. The Serb population, estimated at 100,000 to 120,000 persons, is largely Serbian Orthodox. Kosovo is densely covered by numerous Serb Orthodox churches and monasteries.
Where do they practice their faith? Wherever their faith takes them.
If you are meeting so many, why not ask them?