Progressively filtering form against one table

[SueBK]

I have a table that has four fields (plus others not relevant to this discussion):
-region
-area
-road
-activity

I want to create a form that is filtered for a specific road. I can create a form with a combo box "choose from this list" and a button to open the filtered form.

Rather than users wading through a list of hundreds, I thought it would be easier to create a separate combo box for each of the fields; that is, the user chooses one of the four regions, which filters the area combo box; they choose the area, which filters the road list; they choose the road, which filters the activity list.

Is it possible to write this without separate queries to attach to each combo box?

 

[SueBK]

What I'm trying to do:
Region field has four records
Area field has numerous records against each region (and confusingly, I've discovered, a couple of areas that occur in more than one region).
Roads occur in an area.
Activity on a road can be one of two options.
SO:
"repair works" (activity) are occuring on "Annadale Road" (road) in "east cloud 4" (area) in "east 1" (region).
I want a form that filters against a specific record (activity on a road). I can create a single combo that shows all four fields for users to scroll through; but that can get tedious when you've got 100s of records.
I wanted a series of combo boxes. Using the example above:
When 'east 1' is chosen in the region combo box, only the areas that occur in that region are available in the 2nd combo box.
When "east cloud 4" is chosen from the 2nd box, only roads occuring in that area are available in the 3rd combo box.
When Annadale Road is chosen in the 3rd box, only activities occuring on that road are available in the final box.
The user then clicks the 'go to form' button, which opens a form filtered for that specific record.