Hi - I am setting up two stores that will run from the same Access db. MOST of the products overlap, but there are a few that can appear only in one store or the other.  I am approaching it by adding a field to the product table that identifies whether the product should appear in just Store A,  just Store B, or both.

Each store will also have a different set of categories. The categories are set into two family "branches" - has anyone edited the incCatMenuA to start the display from a LOWER category level? Any advice appreciated, especially as it relates to foreseeable problems, as I am fairly new at this. 

Thanks in advance.

First, you will most likely need to purchase two Product Cart licenses to run two stores, even if they share a database.

There are quite a few ASP pages that you need to add checks for product displays to skip products not available for a specific store...
1. Regular and advanced searches. The advanced search page can show categories as well.
2. The Browse Catalog page starts at the top level category
3. Specials, Featured Products, New Arrivals, Best Sellers

For the inc_CatMenuA, around line 108 you should see code like the following:

'----- Start Categories Level 1
query="select idcategory,categorydesc from categories where idParentCategory=1 and idCategory>1 and iBTOhide=0 " & pcv_strTemp & " ORDER BY priority, categoryDesc ASC"

Change the "1" in "idParentCategory=1" to the idCategory for the top level category in the specific store. That should start your list with the categories directly below the cateegory you specify.