Hi @Nikunj,
Welcome to the forum .
Unless you were to add in functionality to your token which restricted transfer until a certain date had passed, then a transaction to release tokens per holder is required. (as we can’t loop through a large number of holders to release as we would run out of gas).
My preference is that a token should only have functionality that is required for the life of the token and not contain short term functionality. So any locking should be done in a separate contract.
You could look at the vault idea in PostDeliveryCrowdsale to do some of your locking.
When ever anyone is creating a token, I suggest reading: Points to consider when creating a fungible token (ERC20, ERC777)