If they are feral it will be tough.
Oklahoma - Paws of Tulsahttp://www.pawsoftulsa.org/
Might be able to help. without being able to come into contact with the animals there is not much that you can do directly. Best thing would to be able to arrange a capture and release operation with humane traps with a feral cat rescue organization. Medicate them, NEUTER them and then release.
If you can notice that the babies have really bloated tummies, then yes they are infested with wurms. If possible to capture the babies, 1 simple pill will take care of the worms, contact your vet. be honest with what you are trying to accomplish you may get samples for free.
You may want to try "sevin dust" or similar near the foundation of your home to keep the fleas away from your house. Cats will usually avoid this pesticide due to its smell. Just make sure that no food matter that you feed or they coud forage comes into contact with the dust and they will be ok.
If you have indoor cats or outdoor cats of your own KEEP them AWAY from the yard and worm infested fecal matter.
Make very sure that any contact you have with these feral cats or their droppings. CLEAN your hands clothing etc before coming in contact with your domestic cats. You dont want to transfer anything to your indoor babies. Feral cat communities are usually full of cats that have very communicable illness.
I hope this helps.