The Czechs will meet Serbia in a three-match showdown Saturday for the championship.
After two singles matches involving players from the Czech Republic and Argentina were split, Stepanek and Cermak clinched the round-robin matchup by defeating Carlos Berlocq and Leonardo Mayer 6-4, 4-6, 10-3.
The third set involved a special scoring system in which the first team to 10 points with at least a two-point lead won the match.
That win gave the Czech Republic the Red Group title while Serbia captured the Blue Group thanks to a 2-1 win over Germany. Janko Tipsarevic gave Serbia an unbeatable 2-0 lead when he defeated Philipp Kohlschreiber 6-4, 3-6, 7-5.
Germany missed out on a chance to win the event for the second straight year and for a record fifth time overall.