If you already send from multiple email addresses in Gmail, you also have the option to use them with the Employee Email extension for Gmail.

In Gmail, click the Settings button for the Employee Email extension then click Alias Management.

Options when using multiple aliases:

• Track from the primary account i.e. if you log into john@gmail.com and track and a message from an alias (johndoe@gmail.com), the email is tracked in the john@gmail.com account in Employee Email, as this would be your Primary gmail account.
• Track to its own account i.e. if you log into john@gmail.com and track a message from an alias (johndoe@gmail.com), the email is tracked in the johndoe@gmail.com account in Employee Email. Note that with this option, your alias and your primary account are completely separate.