Same happened to me some years ago. If they can be handled there is a good possibility they could be homed. Cat Protection at 01-2761850/086-1653197 are very helpful or Animal Welfare Veterinary Hospital in Charlemont Street, 01-6714303. If you can put them into a box and take them to the vet that's probably the most humane option. Ideally the mother cat should also be caught and spayed. Cat Protection would arrange to do that.
It's a sad fact of life that there are about a million feral cats in the Dublin area who are multiplying at an exponential rate. Neutering and spaying would prevent that.