In order for multi-sourcing to be successful, organisations must be capable of integrating their service providers into a single, cohesive unit.
SIAM/MSI – An introduction to Service Integration and Management/Multi-sourcing Integration for IT Service Management explains:
If you're thinking of moving from a single-source to a multi-source outsourcing model, SIAM/MSI – An introduction to Service Integration and Management/Multi-sourcing Integration for IT Service Management provides the answers to all of your questions.