Smallcase as a use-case a very different from our use-case of Portfolio. Your’s is a very advanced use-case, mostly more like a mutual fund - every every basket or portfolio has a different use-case.
Any API we provide to solve for this, will also not serve this purpose - reason being stocks (like cash) when in demat format is fungible. So your stocks can be labelled only when you buy all of them and sell all of them at the same time, otherwise they come and go as fifo method with every transaction.
We introduced this small feature that many users like, I personally do is marking my long term portfolio separately, more on that here: Now mark your Long-Term Portfolio separately on Dhan