Sheilla, this is a common situation in brazilian contracts but unfortunately you can only have 1 supplier per Master Agreement/Agreement.
You can follow one of this options
- Create a Sub-Agreement with the other supplier.
- Create another Master Agreement and link both of them through Contract Hierarchy (Version 9.0 onwards)
- Create extension fields in order to show the other vendors just as information (If you have more that two vendor you would have to consider a Collection).
You should consider the first two options if you are planning to publish those contracts to ECC.
This restriction is also because on SAP ECC Outline Agreements we can only have one vendor per Contract/Schedule Agreement, so as CLM is integrated with ECC it wouldn't make sense to allow multiple vendors in only one Master Agreement/Agreement.
BR,
Robert