Waters Retail Group, whose dealerships are branded Autoplanet, has taken over Tunbridge Wells Kia and Seat.
The group, headed by chief executive Darren Payne since his MBO last year, bought the business from Humphries & Parks, which continues to represent Mitsubishi in West Malling.
Payne said: "We are extremely pleased with the acquisition as it fits our strategy and also is our first venture with the Seat brand and VW Group."
Waters now represents Kia at three sites of its 14 sales points.
The deal was brokered by ASE Dealermatch. David Kendrick, transaction manager, said: "Yet again we see another group purchasing a going concern from a smaller business as the consolidation in the sector continues."