Whatto do about abandoned dogs?

Where I live, in the country, people seem to dump their dogs there, they just come along in their cars, put the dogs out and drive off. We live in the country in Ireland and my family and I just can't watch them suffer so we usually end up taking them in and looking after them even though we already have nine dogs of our own. All of our own dogs have their own individual dog pens outside so none of our animals live in the house because that would be really smelly!! We have ended up buying five spare dog pens for the strays and usually one or two dogs are abandoned per month. We have to buy loads of food for them and then we rehome them. We're getting sick of people dumping their animals and we tried to get one man's license plate but he had it covered! How can we deal with this or should we just keep looking after the animals, and because I have a 5 year old sister, she could get hurt if one of the dogs were aggressive and attacked her.

Seven weeks ago, a springer was left, and a few weeks later we found out she was pregnant. She's had her puppies and we have a waiting list of people looking to buy them, there is 11 people looking to buy them but there is only 4 pups. We offered them other dogs and pups but they don't want them.

So far this year this is what we've taken in:

-male labrador cross

-female labrador

-two female hounds, abandoned together

-female terrier cross

-male jack russel

All of these animals, we have found homes for but we still have

-four terrier puppies, abandoned in a box together

-female spaniel cross

-male greyhound

How can we stop people abandoning more dogs or do about the dogs? We won't give them to shelters a there are already enough dogs in the shelters. There are no dog shelters or dog charities near us either. Thanks