That's a good idea in theory, the thing with catch alls is that it makes the domain very susceptible to spam so the random spammer can get through lots of mail by sending to
anything@domain.com or
commonname@domain.com , etc.
However, you can certainly make use of it, by using the content filters too.
There are a number of ways to do it, depend on what you would like.
You could setup the catch all
Then create a content filter that deletes messages if it’s going to
userbeingspammed@domain.com
Or you could setup the catch all
Then in the content filters, set it up to only deliver messages to your domain that matches a list of user names, you would then need to update it each time a new email was made.
There are probably other combination of filters that would do what you are looking for, just take a look at the filter options and you should get a good sense of what you want to setup.
