Sales order work order relationships to be maintained

Using MRP planning.

Have Structure as below:

FG1

-SA1 (MAke item but planned from 3rd party)

-RM1

-RM2

SA1 (Make Item)

-RM3

-RM4

Sales order1 is created for FG1.

Now planned orders are suggested from MRP.

I want the link or reservations of these work orders and sales orders to be maintained, So that the lot produced from these work orders are not utilized for other orders

Please suggest.

Thanks,

Jey