Help me save neighborhood cats?

My wife and I live in a enclosed urban apartment building in China. There are a handful of feral cats that hang out on the awnings and platforms around the building and in the building's courtyard. They have started annoying the residents with fighting and howling at night. Last night some of the door watchmen tried but failed to catch the cats. If they catch them they will kill them. Soon they will no doubt attempt to poison them. I would like suggestions on how to catch the cats myself so I can have them spayed/neutered and released elsewhere before others kill them.