I believe you said you live at the south shore? I think that may be too far for http://www.secondchancefund.org/index.html
as they are in Worcester county, but they should be able to steer you to someone who can help.
I'm also in the same situation as you are, but with their help I've trapped 4 cats so far, 3 kittens and 1 adult male. The adult and 1 kitten are people friendly, so are adoptable. The other 2 kittens were too afraid of people so were released after being altered. There are (at least) 4 more I would like to see trapped. The mom of the kittens and her daughter, the "grandma" of these two, and a littermate (I think) of the mom.
These are the only ones I see on my deck, though I know there are others, but are too afraid of people to come to my deck.
I currently have the adult male and kitten in my bathroom. The adult is going to someone tonight until a home can be found for him (he's FIV+), and the kitten will be going to a no-kill shelter on Sunday. They should have no problems finding him a home as he is the sweetest and friendliest kitten you've ever seen. He absolutely demands attention by wrapping himself around your ankles (and kneading them) and he loves to flop onto his back so you can play with his belly. I was brushing him last night and it was putting him to sleep. He also has a purr engine that doesn't quit. It's hard to believe this is a semi-feral kitten born to a semi-feral mom, etc. etc.
Good luck in capturing your "tenants". It gives you a wonderful feeling knowing that you're making their life just a little bit easier.