how can have this url car1?category=blue car?category=red car2?category=blue for drupal 6.x
I have a vocabulary with terms
car1
car2

and a vocabulary with terms
red
blue
yellow

how can to do this
2 menu 
1) car1 | car2     (this really how a select)

2) Allcolor |  red  |  blue  |  yellow    

3) here the results 

when I click on car1 I have a page with all the car1's color nodes (and the Allcolor menu active)
url think so must to be: 
/car1

if I click on red I have the result of car1 red nodes
/car1?category=red
if select blue
/car1?category=blue

when am on red under car1 and click on car2 I have the red car2 results
/car2?category=red

not sure if the url is so, but which is solution for to do this
functionality?

I know that is simple with only one vocabulary type this
car1
  red
  blue
  yellow
car2
  red
  blue
  yellow

but I must to do with distinct vocabulary; the terms really are more
for every views is necessary to have one exposed; 
but isn't possible manage the 

1) car1 | car2                        menu1
2) Allcolor | red | blue | yellow     menu2

menu2 how a submenu of menu1, also if isn't a unique vocabulary?