How to make the coud supply planning engine to suggests the planned order with either Primary or Alt

Summary

What setup is required in oracle fusion to make the cloud supply planning to sugesst only one production line throughout make of one end item

Content

 We are having end item defined with 2 work definitions(line1 with priority1) & (line2 with priority2) and in the same way we defined subassemblies with 2 work definitions(line1 with priority1) & (line2 with priority2). We enabled alternate item structure and work definition in constraint planning. Planning currently suggest planned order for end item with line1 wordefintion and for its subassemblies its suggesting with line2 work definition. Our requirement is to have output as planning should use either Line1 from top(end item) to bottom item or line2. what is the setup we require for enabling the below requirement.