Melt margarine in a large nonstick skillet over medium-high heat. Add mushrooms, bell pepper, onions, and garlic; sauté 5 minutes or until vegetables are tender. Set aside; keep warm.
Combine salt and broth in a large saucepan; bring to a boil. Add rice; cover, reduce heat, and simmer 25 minutes or until liquid is absorbed. Stir in mushroom mixture; cook 1 minute or until thoroughly heated. Stir in pecans.