GTE Corp. yesterday said it had realigned its businesses into three groups and appointed three officers to head the groups as it focuses on increasingly tough international and domestic telecommunications markets.

The reorganization splits two groups of businesses into three, creating a new communications group for voice, video and data services in addition to GTE's telephone operations and diversified products groups.

"This restructuring responds to the new competitive environment resulting from deregulation, the breakup of the Bell System and increased foreign competition," said the company's chairman and chief executive officer, Theodore F. Brophy.

"It represents increased emphasis on the competitive intercity communications businesses and the development of new products to serve the Bell operating companies and business and residential customers both here and abroad," he said.

GTE's telephone operations had revenue of $8.9 billion for the 12 months ended Sept. 30, 1984. The diversified products group, which consists of manufacturing and research and development operations, had net sales of $4.2 billion for the same period, and communications services had revenue of $1.2 billion.

The restructuring consolidates GTE's diversified products group, composed of worldwide manufacturing and product development businesses, at a time when U.S. manufacturers are increasingly concerned about entry into foreign markets.

The consolidation will aid GTE in resolving some of the issues, Brophy said. "This reorganization will allow us to focus talent on these competitive issues and focus executive time on those foreign markets," Brophy said in a telephone interview.