Hi @surajc Suraj,
Indian markets are now set to move to T-day settlement in 2024; so even if we build something like this - it will be irrelevant in few months. Additionally, once stocks are delivered to the demat account and reflect in portfolio, they will always sold on FIFO basis.
We help used mark their long term stocks separately, this is used by many of our users. More on that here - Now mark your Long-Term Portfolio separately on Dhan