I have already replied to your email or the comment about this question.
Currently, there is no option to record multiple purchases for shares of same scrip in the opening balances in tally.
I am very grateful to have you posted this question here, but there is no direct or indirect option in tally to do that right now.
What you can do is pass the average entry. That can be done in the following way.
10 x 100 = 1000
5 x 150 = 750
So, total will be 1750. Now, 1750/15 = 116.67 per share.
You can enter the amount of 116.67 per share with 15 shares purchased in the opening balance of the Reliance Ledger.
There is no need to pass the entry for this.
Although, if someone else knows any other method, suggestions are always welcome and that is what this forum is for.