Multiple Drop Down XML formatting

[mjbehrii]

I have data that form a drop down. Depending on what is chosen from that dropdown another dropdown is displayed from data within the XML. I'm looking for the proper formatting of that in XML.

For example:
Main Drop down:
A
B

A links to
A1
A2
A3

B links to
B1
B2
B3

A1 then links to
A1a
A1b
A1c

A2 then links to:
A2a
A2b
A2c

So on and so forth


A/B is a dropdown
If A is chosen A1/A2/A3 displayed as dropdown
If A1 Chosen A1a/A1b/A1c is displayed as dropdown

Thanks for any help.
Let me know if you need any clarification.