Heat oil in a large skillet with a lid over medium heat until oil is shimmering or a drop of water flicked in ti dances.
Arrange sausages in pan and cook until brown on sides, rotating sausages a few times, between 5 and 6 minutes.
Tilt skillet and carefully remove excess fat with paper towel.
Distribute grapes, garlic, mushrooms, peppers and onion over and around sausages. Add water or broth and immediately cover.
Cook, turning sausages at least once, until they reach 160 degrees and onions, mushrooms, peppers and grapes have softened, about 10 minutes.
Transfer sausages to a plate with paper towel.
Return skillet to medium-high heat and add pepper and salt into mixture.
Spread grape-onion mixture in even layer in skillet and cook without stirring until browned, 3 to 5 minutes.
Stir and continue to cook until mixture is browned, about 3 minutes longer.
Reduce heat to medium, add wine and oregano, and cook until wine is reduced, 2-4 minutes.
Remove pan from heat and add vinegar. Serve sausages with grape mixture on top or beside. Enjoy!