cat breastfeeding

my 24 week old kitten is feeding of her aunt they are both spayed and we got them of a person on the may land so cant give one back  the aunt has had kittens in the past so still has the milk and the kittens is eating solid food as well what can we do to stop them feeding as cant keep them apart ?

the aunt is only 1 1/2 

Such a nursing isnt necessary dangerous nor harmful, as long as she doenst overdo it, and the aunt dont mind it.

Its surely nice and cozy for her, and perhaps also the aunt.  

So I really dont think you need to do anything, if you are OK with it.

If you want to do something, so perhaps try with more entertainment and exercise for both of them.   Are they inside only?   Perhaps a innetted balcony. Or a bird feeder outside the window. Climibning trees - you can make it yourself, so they can climb and balance and have lotsa of fun...

If they aunt has milk for real, and dont mind to have someone nurising on it, you can perhaps cooperate with a shelter, or a vet, or others in need, and help orphaned kittens.  Or kittens whomse mom got a very big litter, or got sick and cant manage alone them all...

The permanent producing of milk isnt necessary dangerous by itself, if she gets good food.  In the old times, there was an occupation of professional milk giving extra moms.  Sometimes they used women who had their own child simultaneously (breast-brothers, no?   ),   but often they were professional, who had their child years ago, but continued to produce milk, as long as the milk was in demand.  Some could go into their fifties.

Good luck!