I have a spreadsheet with a column of names and email addresses. I have to
replace these with a last name and first initial that can be found on another
worksheet. The problem is that each cell contains more than one name and/or
email address, and they all have to stay that way. So, for instance, if I
have all of the following in cell A1:

John Smith, Jane Doe, F. Smith,

I want to get the following result also still in one cell:

Smith, J, Doe, J, Smith, F, Green, A

The other problem is the way that the data is set up on the other worksheet.
It is set up like this:

John Smith Smith, J
J. Smith
Andrew Green Green, A A. Green
Fred Smith Smith, F
F. Smith
Jane Doe Doe, J
J. Doe

The match might not be found in the same column every time, so I dont think
a function like VLOOKUP would work. Im not sure that any of the regular
functions would work. I think it probably needs a macro.

Is what Im trying to do even possible?

Thanks in advance for any information.