What would happen if workers in just one department of your company want to join a union? No big deal you say ” as long as those workers do not constitute a majority of employees throughout the company, they would be unable to muster enough support to force a union election.

But a recent National Labor Relations Board (NLRB) decision involving retail workers in Massachusetts underscores the fact that small groups of employees now have the ability to carve out “micro-unions” within a larger work force.

The NLRB recently allowed a union election to proceed within the Macy’s store located in Saugus, even though the union seeks to represent only employees who work at the cosmetics and fragrances counter – 41 of the store’s 120 workers. The federal agency relied for its decision on a 2011 ruling involving Specialty Healthcare, a rehabilitation center, where a group of nursing assistants wanted to organize.

Macy’s said it was “disappointed” with the board’s decision.

“Organizing a selected portion of a store’s selling associates into multiple collective bargaining units is impractical and an impediment to providing a consistent level of customer service,” Macy’s said in a statement.

Reuters reports that the company is considering challenging the NLRB ruling in court.

The Specialty Health Care decision was initially supposed to affect only health-care facilities, but the Macy’s decision leaves little doubt that the federal government will permit micro-unions across virtually all industries. Employers face the possibility that a small percentage of their employees, within loosely-defined departmental or functional boundaries, can effectively pursue union representation.

The prospect of the NLRB subdividing a work force into mini communities of interest is a disaster for employers. Organizing smaller groups is easier, quicker and cheaper for unions than persuading full workplaces to sign up. At the same time, conflicting work rules, pay and benefits in adjacent departments make it incredibly difficult for the employer to manage.

My many decades in labor relations have taught me that employers must remain aware of the issues that can cause employees to look elsewhere for the respect, appreciation, fairness, security, wages and benefits that drive the union’s appeal. Analyze your vulnerability, create strategies to make unions unnecessary and train your team to recognize the signs of union intervention.