How to make VLOOKUP return multiple error values

Hi all

Not sure if this is possible, but what I am trying to do is a regular VLOOKUP with the caveat that:

• Where the lookup value is an empty cell, instead of N/A, the formula returns "Unknown"
• Where the lookup value is missing from the table array, but is NOT an empty cell, the formula returns N/A (as usual.)

So far I have only been able to use an IFERROR to pull back "Unknown" for all missing values in the table array. 

Is this even possible?

Many thanks 🙂