Third party help
I've often mentioned that it's a good idea for neighbours to speak directly with their neighbours if they have a problem with the situation. However in some cases, the complaint about the cat is just one of the matters under contention - in some cases, it may not be about the cats at all, but that the cats are the easiest ones to complain about and strike out at.
In this case, if you are one of the caregivers involved in a situation like this, please do NOT attempt to speak to your neighbour (or another resident, or even someone who is always in your estate for some reason). What you should do is ask a third party to come in.
We have a case today where two neighbours are not getting along and the community cats are one of the issues raised - emotions are running high obviously. If either party tries to talk to the other, I think the situation will just get uglier and the cats may well suffer. One neighbour has already asked for a cat trap to trap the cats. Unfortunately, the management committee does not seem to want us to go in and help (despite my phone calls and emails).