conditional vlookup

First post, so hopefully this is the right place for the answer!

I currently use VLOOKUP to return a value from other spreadsheets.

However, I need Excel to firstly check the contents of a particular cell, and then decide which spreadsheet to look up.

So, for example if the vaule in cell C3 = 1 then VLOOKUP spreadsheet "ABC", if value in cell C3=2 then VLOOKUP spreadsheet "XYZ" and so on.

Any ideas?