Dear Krish Hait
I suppose you are using MRP type PD or something like this (planning to demand) without safety stock (MTO).
In this case, if any demand appears, system will propose a replanishment. No matter what is your fixed, min ou max batch... an planned order will be created if any demand appears...
First of all, keep in mind that it is up to you (or your planner) to convert the proposed planned order into a firm order, or keep it as planned until it reaches the minimum production/purchese you want.
Then you can simply determinate and agree with your stuff that the orders will be manually converted in your MD04 collective access just when it reaches the min batch.
Do not forget: planning is much more about right decisions of planner than automatic moves. Of course, a strong, wise, solid MD and customazing behind it to enhance the decisons' accuracy is a must!!
Best regards.