Police Scotland said it was investigating a spate of scams performed by the group in Dumfries & Galloway as well as Cumbria in recent weeks.
The men, who are “very convincing and persistent” according to officers, flag down passing motorists and ask for money - claiming to have run out of fuel.
“They will ask for cash, or money to be transferred into an account,” police said.
“They will sometimes stand in front of cars to make them stop or prevent them from moving off.”
The group’s luxury cars are said to bear German license plates.
Police Scotland told Scots: “If you see such behaviour then please don't engage with them and phone Police on 101 or - in an emergency - 999.”