Dual sourcing with demand split in SAP APO

Hi Expets,

Need your Expertise here,

We need to set up a demand split situation in SAP APO, when the capacity of the primary vendor is reached the remaining demand should be posted to the second vendor.

for example if the capacity of the primary vendor is 100 and if the requirement is 150 for the bucket, the 100 should flow to the primary vendor and the remaining 50 should be to the second vendor.

If the requirement is only 75 (which is less than the capacity(100) of the primary vendor) the entire demand should flow to the primary vendor only.

Please provide your comments on this and help me in meeting this requirement. Thanks in advance !!

Regards,

Yasar