Your best bet is to check with the rack suppliers/manufacturers.
Try www.leasure-mart.co.uk Vehicle Cycle Carrier (BC2060)
They say it takes up to four bikes and might suit your purpose, Befor contacting them have the measurements of the width of the vehicle and the width of the sections either side of the door and measure the adult bikes for length in case the bikes when fitted to the carrier, overlap too much for it to be legal to use the carrier.The supplier should be able to tell you this.
Bob
May 2010