Virtual domains for foo@*.foo.com

We have a need for wildcard third level virtual domains in postfix.
For example I registered foo.com and set up a virtural domain so that
all mail to foo.com is received by my postfix server. I also have a
way that users can generate their own third level domains off of
foo.com (e.g. example1.foo.com, example2.foo.com, etc.).

I would love to be able to set up something like...
@*.foo.com foo.com/
...in my virtual mailbox file so that all of the new third level
domains can be routed to the foo.com mailbox. Is this possible?

Thanks