Filter duplicates based on criteria / column values
 

I have an e-mail contact list that I need to filter.

Column A = E-mail Address
Column B = Company Name

Alot of people from the same company may be on the list, so in Column B
there will be alot of repetition while the co-responding values in Column A
would be unique.

Sometimes a company name will be listed but we don't have the e-mail
address, so the value in Column A would be blank. Sometimes a company name
will be listed with both e-mail addresses and blank values (in Column A).

I'd like to do a few things:
1) Filter the list so that all dupliate company names are deleted, but the
remaining single listing should be the one with an e-mail address (not a
blank, any e-mail address).
2) Filter so that I can have a list of companies with no e-mail address (so
that I can call them and ask).

Much thanks!