Catch All Email Addresses

Hello!  We have just migrated our user base from H-Sphere to HC8.  What a change!  But we are getting the hang of things for the most part.
 
I do have a user who is looking for a function that, in H-Sphere, we called Catch All Email Address.  I have also seen these called Default Address in other systems.  To be clear what we're looking for, they want for people to be able to send mail to any address @theirdomain.com and have it forward over to this catch all address.
Is there such a feature or function in HC8?  If so, how do we set that up?  I did email support about this, but to be honest, their response didn't make much sense to us.  It sounded like there was a way to set this up through webmail?
 
Thanks for your help!
 
Mark