This was what I had from the newgroup of EXIM... bascally more legal issue that the actual of can we or can we not do.
'Catch all' is a form of 'dead letter office', wherein one places traffic with no genuine/identifiable adressee. You really don't want to go there, as it is nearly all spam/mal-code, not spelling-errors, and is lmited only by lax rules and available bandwidth.
Google 'Big brother archiving', 'Facist Logging', 'shadow transport' 'unseen (routers)' to find what you want on records retention.
Bring lots of disk space, and file away a copy for yourself of the 'Company Policy' announcement to staff making them aware that this will be in effect, as well as a 'CYA' letter from Corporate Legal Department w/r 'law of the land' in (at least) your own jurisdiction.
Not to mention other jurisdictions where your firm's correspondents reside that you may someday wish to visit freely ...