In this case I am using same material for MRP run.
Screenshot 1: contains the selection parameter in both MD01N and MD03 transaction.

Screenshot 2: MRP result after running MD01N - you can note that 2 requisition were created
Screenshot 3: MRP result after running MD03 transaction- here system created a collective PR.
Business requirement is to create a single requisition considering all the open requirement as on date before running the MRP.
NOTE:
1. I have considered MRP type as PD;
2. collective indicator 2 in MRP4 view
3. custom lot size where the period is 12.