How can I create a sublist for a list?

Hi,

I have Subsidiary A Listed with multiple Values, and for each value, there are multiple values; I create the value list on the subsidiary page, so now I have

Also Please note that the Value A or Value B or Value C will be changed based on Subsidiary and Currency

--------------------------------------List --------------Sub List

So now: Subsidiary A -------------- Value A

------------------------------- Value A-A

------------------------------- Value A-B

------------------------------- Value A-C

-------------- Value B

------------------------------- Value B-A

------------------------------- Value B-B

------------------------------- Value B-C

-------------- Value C

------------------------------- Value C-A

------------------------------- Value C-B

------------------------------- Value C-C

So How I can do this sublist?