Find first value (from a list) which appears prior to target value

[T15K]

Hello,
I have quite a complex problem but any assistance provided would be gratefully received.

I have attached an example spreadsheet that shows my problem. Basically, in column A I have several thousand rows of 3 or 4 letter codes. In column B, I need a formula that will find one particular target code in Col A and then in the adjacent cell in Col B, display the first code to appear in Col A above the target code which matches the list of desired codes.

So the briefly re-state the problem, I need a formula which finds every case of one particular code in Col A (in the example spreadsheet the code is ABCD), and then read back up Col A to find the first value which matches the desired code (from a list of about 5-10 codes), ignoring other values which represent codes that are not on the list, and place this col B adjacent to the target code.

I thank you in advance for your assistance

T15K