Conditional VLOOKUP?

Hi all! I've got two sheets, sheet 1 and 2 (attached). Basically, I need the Number column in Sheet 2 to be filled up with Sheet 1 as the reference for the needed data. The problem is that some entries in Sheet 1 have the same ID but are from different Groups. For example, AAA Inc. has an ID of AAA but can be in either LMFI_AAA or LMFII_AAA. So, I basically need some sort of VLOOKUP that recognizes the Group or something like that. Any help would be greatly appreciated.

http://www.excelforum.com/attachment...tid=3976&stc=1
http://www.excelforum.com/attachment...tid=3977&stc=1