Since I received the go-ahead to explain my point, I will try to make my case.
Our company operates 5 websites. Each website is catered to a specific target market and is specifically designed for the intended target market.
The main site is invitationconsultants.com. The other sites are birth-announcements-store.com, wedding-invitations-store.com, graduation-announcements-store.com, holiday-cards-store.com.
They are not mere mirror sites of the main site. Each site has separate toll-free numbers and a dedicated staff for each one of them.
Although there might be some overlap as to the products sold, some products can only be bought on certain sites.
Each site also contains unique content.
For example:
www.wedding-invitations-store.com contains an 'Invitation Guide' with wedding etiquette information that is nowhere to be found on our other affiliated sites. The sample wording section is much more elaborate as well.
www.holiday-cards-store.com contains a 'Corporate Corner' with specific information for corporations, as this site is partly geared towards corporate customers, unlike our other sites.
www.birth-announcements-store offers the possiblity to pre-order birth announcements. This feature is specifically designed for birth announcements.
There are more examples.
Conclusion:
Yes, we operate 5 different sites, that are affiated because they are owned by the same company. But I believe each one of them deserves a place in the DMOZ directory, as they are not just mirror sites, but different sites, with a different look and different content targeted for different audiences.