Filtering one Column Based on a Keyword in Another Column

Hey everybody,

I'm having a tricky issue with Excel. Basically I have three columns: One contains numbers, one contains last names, and one contains full names of people.

Number	Last Name	Full Name
1.	Smith	Smith,John
2.	Johnson	Johnson,Smith
3.	Beal	Skywalker,Luke
		Beal,Jane

I want to be able to filter the last column if the last name of somebody appears in the second column.
The catch is that the first two columns are on a different sheet from the last column. I need to be able to filter the last column, paste the numbers in, and then unfilter it.

So right now I have:

Number	Full Name
	Smith,John
	Johnson,Smith
	Skywalker,Luke
	Beal,Jane

And by the end I need to have:

Number	Name
1.	Smith,John
2.	Johnson,Smith
	Skywalker,Luke
3.	Beal,Jane

Does anybody know how I could do this? Sorry if this seems a bit convoluted. Also I have thousands of entries for each column, which is why I can't figure this out manually.

Thanks! :D

I guess a simpler form of this question is: Knowing what number corresponds to what last name in one sheet, how can I translate this to putting these numbers to the corresponding full name on another sheet, leaving blanks for full names that don't appear on the other sheet?