|I think it would be best if you created separate columns for the last names and then compared those lists.|
To strip off the last names from entries like these, try the formula below.
Davey P. Jones
=IF(ISERROR(MID(A5,FIND(" ",A5,FIND(" ",A5)+1)+1,256)),
MID(A5,FIND(" ",A5,FIND(" ",A5)+1)+1,256))
You can then use VLOOKUP to look up each last name from the short list in the longer list and pull the ID from the appropriate column.
If you need help with the VLOOKUP, let us know.
BTW...this won't work if you have 2 people with the same last name since VLOOKUP will only find the first one in the list. I'm sure we could come up with a way to compare both first and last names, but if one list uses Davey and the other uses David, things could get very complicated very fast.