Additional email ability

I would like users to be able to respond directly to the email that is sent when someone fills out the contact form on a listing.
Currently, the user would fill out the Inquire form and an email is sent to the seller saying they received a message.
Instead of having to then login to the website is there a way for the user to just respond to that email and it will be sent to the user? Users & sellers are both registered but I do not necessarily want email addresses to be shown, at least not for initial contact.
Is there something easy to integrate?