I don't know where you live...but I would try to engage a TNR group. Feeding alone will only increase the colony and increase the chances for some of the unsavory individuals to do harm to the cats or call Animal Control to trap and remove them. Below is a list of TNR groups in the USA, even if one isn't in your county, see if you can contact one in your state and find out if they know anyone who does TNR in your area. TNR is the most humane method of reducing the outdoor cat population through spaying/neutering. The cats are returned back outdoors but they can no longer add to the overpopulation through producing unwanted litters of kittens. It's healthier for the cats overall tends to reduce negative behaviors such as fighting and spraying.I know one lady was spaying and neutering, but she just moved. I've never talked with the other people.
http://www.alleycat.org/orgs.html
Katie