We've run a few articles addressing this very problem. The most recent one is "Kitties 'n' Canines in Co-ops 'n' Condos," at this link:

http://www.habitatmag.com/publication_content/habitat_s_purchasing_primer_news_for_new_buyers/kitties_n_canines

but if you do a search for "Pets" in the search box above, you'll find a slew of pieces that will help. You'll find there are good and even revenue-enhancing ways of establishing good-pet policies. Good luck!