In large skillet over medium high heat, brown ground beef; drain and return to skillet.
Stir in green peppers, onion, and beef gravy. Simmer until peppers are tender, about 15 minutes.
Add tomatoes; simmer 5 minutes longer.
Remove from heat and add white wine vinegar and rice. Stir until blended.
Slice pita pockets in ½.
Spoon ground beef mixture into each half of pita and serve.
