A group of illegal immigrants who worked for Wendy’s International Inc. is suing the restaurant chain because the company fired them after discovering it had missed a deadline for joining a federal program that would have helped them attain legal status.

The lawsuit, filed Oct. 6 in state district court in Houston, is a companion to a similar class-action suit filed last month in Dallas against Dublin, Ohio-based Wendy’s, its subsidiary Cafe Express and the Houston-based business law firm Boyar & Miller.