Good way to transfer parent timeseries knowledge( trend/seasonal ) to children?

For example,

I have a category A called fruit, its children are in category B, for example :

• apple
• banana
• ….

The whole category A have been already sold for 3 years , but now we have a new category B fruit call cherry, which only sold for 3 week .

I have thought to transfer trend/seasonal to children , scaled down by the 7 days mean salecount, this method is too simple with many problems .
I don’t know what is the proper name for this kind of problem, it is different from transfer learning in deep learning area .
Is there any smarter way to transfer knowledge in category A to this new category B ? Any thesis are welcome .