Okay, you need to get some help to figure out which cats are owned and indoor/outdoor, which are not. If you are an indoor-only cat owner, you can try to convince your neighbors with indoor/outdoor cats that their pets are better off indoors. (This could be a long-term project in itself, I realize, because I spend lots of time myself trying to convince people!). You can also ask for their help witht he UNowned cats. If you work together, you can come up with a great plan to get the unowned cats sterilized. You might be lucky enough to find out that there's a group like mine in your area, that will help you with this project! If there is no group in your local area, we here on TCS will gladly "coach" you and the team. If you are new to your neighborhood, you may want to enlist the help of someone who owns pets and who has lived in the area for a while, with the team-building, since people might know one another and one another's cats quite well, even if you may not (yet).