Yes. Why are you using SSIS for any of this other than extracting the file from the email? Just do a bulk insert into a staging table, validate the data, and have at the rest as you would with any other "upsert" queries.

Also, if this is something that's supposed to happen on a regular basis, why not just have the other party setup an FTP (or SFTP) and download the files instead of messing with emails?