Show subform on Form completion, and pass variable?

Show subform on Form completion, and pass variable?

Hi - we'd like to have a Parent/Child subform scenario. When the Form initially loads, we'd like to hide the subforms (we know how to do this). The parent will be related to various subforms/tables. Our example is this:

We have a products table (the parent). In that products table, we'll have
-Product Type (Drive, Server, Laptop, etc drop down)
-Manufacturer (Intel, Dell, Asus, etc drop down)
-Model Number (single line text)

We then would have several ProductDetails children tables, each with their own attributes. One table per product type. Tor example in the above scenario we'd have

-DriveDetails table (CapacityGB, RPM, etc. fields)
-ServerDetails table (Server related details fields here)
-LaptopDetails table (ScreenSize, weight, other laptop detail fields here)

On Save/Success of the parent "Products" form, we'd like to show the relevant subform, but only the *relevant* one, basing the hide/show off of the product type chosen above. Also to tie the two records together we'd have to pass the productID or some other identifier from the newly saved record down to the subform.

How do we do this??