It depends on the wording of the Rules/ terms stipulated in the Memorandum of Association of your cooperative society. If the MOA categorically prohibits feeding of animals, then no resident of your society is legally permitted to feed the same-feline or otherwise.
Your case is weak on two grounds. Firstly, the act of the family(ies) in feeding the kittens is not occuring within your premises. Hence, no actionable claim lies on your part, as you have not been adversely affected in any way. Secondly, no other person excluding you has ever seen the accused families feeding the cat, as per facts of your case. There is a possibility that your claims may be rebutted on grounds of it being hearsay evidence.
Please collect evidence (eg. pictures/videos) showing that the accused families are actually feeding the animal). Once you have adequate pictures/videos then only approach the management of your society for relief. Your co-op society management/managing committee can take strong action/ban such activities only when you satisfactorily prove, through pyisical/electronic evidence, that the persons you are naming as feeding the animal have actually fed it & not based on your own personal knowledge.
For further queries you may contact me at: basu_kunal@hotmail.com. I will be only to happy to advise you on further legal recourses.
Regards
Advocate Kaybee