A group of 41 cosmetics and fragrances workers at a Macy's Inc. store in Massachusetts is large enough to attempt to unionize, the National Labor Relations Board decided in a ruling that could advance organized labor's quest to unionize subsets of workers in varied industries.

In a 3-1 decision issued Tuesday that sided with the United Food and Commercial Workers union and raised concerns among business groups that it would lead to fragmented workplaces, the board's three Democrats said the workers at the store in Saugus,...