The impossible pull down menu!!!

If someone can assist me with this I will be so happy!!

Here is the situation: A two sheet spreadsheet. Sheet one is a form and sheet 2 is a hidden page that contains the list and named ranges for all the pull down lists on sheet 1. On sheet 1 there is a colunm that contains a pull downlist, it works fine. The column next to it contains cells which have pull down list that are dynamic based upon the selection made in the first pull down list. I did this by using the indirect(...) function in the source space in the data validation box. This works fine.

The problem is: I want the selection made in pull down 2 to change once a selection has been made to show a diffrent value. For example: If pull down 2 contained a list of all 50 states by full name and the user selects Texas I want the data shown in the box to be the abbreviation for Texas, TX, rather than the actual word "Texas".

I have the data on sheet 2 and can easily make this work using a simple vlookup, but I cannot seem to get the vlookup to work nested inside the indirect function in the source section of the data validation creation box.

I am hoping someone may assist.

I do know that I could add a column in and have the vlookup function work, but I want it all to be done within one cell. Please assist....