nested groups + show records with no category

Hi,

I'm pretty new to crystal reports and just figuring things out. These are really 2 separate questions (I'll split up the points accordingly).

1) Right now I can group the records fine if it's a single group, but problems start occurring with 2 groups. Here's an example: let's say I have records of cars. Each car has a color and year. In the database I would have 5 tables: CARS, CARS_COLOR, CARS_YEAR, COLOR, YEAR. CARS_COLOR contains the primary keys to link CARS and COLOR, same goes for CARS_YEAR.

In my report I'd like it displayed this way:

2000 [field in YEAR]
    Red [field in COLOR]
        Car 1a [field in CARS]
        Car 1b
    Blue
        Car 1c
2001
    Red
        Car 2a
    Green
        Car 2b
        ...etc...

So, I can group cars by year fine and by color fine. The problem is grouping by both. I thought about making a subreport, but I don't know how to filter the subreport (using the select wizard) to only display cars for a specific year.


2) Also, some cars may not have an assigned color. (In other words, no record exists in the CARS_COLOR, so the "unlinked" record in CARS is not shown.) However, I still want to display these cars, under the group header "Color Unavailable". (Otherwise they won't show up in the report.) What's the best/easiest way to do this?

Thanks for all your help!