The simple answer is yes and no.
It all depends on what services your provider allows. My provider (see sig line) allows me to run scripts as the recipient of emails addressed to any email address I choose.
With this method I can direct the email to me and to the script, the script then reads the email to get the from header and then can look up a database of people to reply to. - piece of cake.
Most providers do not seem to allow this and the alternative is not as nice and not as seemless.
You could direct all email to a special pop box and write a script run from a cron job to check for new email every 'n' minutes and then basically duplicate the process described above.
This will work but there will be a delay between the email being received and the reply being sent which personally I can live without.
If you have not alreday got a host who allows emails to be directed to a script upon receipt then you might consider moving to one who does, it allows a lot of nice systems to be built based on email triggers.
