Sounds like you have an earth fault in boot or rear light clusters are faulty.
I've not had any bulbs blow apart from front main beams which I changed to a brighter type - they only lasted a year (I keep lights on all the time).
New Company car 2011 BMW F10 520D SE Xirallic Imperial blue/Cinnamon Brown 6FL USB, Front Sports seats, Sports steering wheel, Xenons - Arrived 3rd Dec 2010!
Scrapped RIP 12/08/2010 - E90 320si - Le Mans Blue - Totally standard specification
Long gone - 00 Peugeot 306 2.0 SE Cabriolet, 94 Rover 214 SEi, 91 Fiat Uno 60S Mk2