Swarming is a technique to more effectively resolve complicated and complex issues, which typically require more than one person or group to complete an activity effectively1. Swarming involves stakeholders working together to resolve the issue, rather than escalating it through a tiered structure2. Swarming can reduce the time to resolution, improve the customer experience, and enhance the knowledge sharing and collaboration among the support teams3. Swarming is also a concept used in Agile and DevOps methodologies, which are part of the ITIL 4 framework4.

Service integration and management (SIAM) is a management methodology that can help coordinate multiple service providers and ensure consistent and seamless service delivery to the customers. However, SIAM is not a technique to resolve complex incidents within an organization, but rather a way to manage the relationships and interactions among different service providers.

Machine learning is a branch of artificial intelligence that enables systems to learn from data and improve their performance without explicit programming. Machine learning can help automate some aspects of service management, such as incident classification, routing, and resolution. However, machine learning is not a technique to resolve complex incidents that require human intervention and collaboration.

An information model is a representation of concepts, relationships, constraints, rules, and operations to specify the semantics of something. An information model can help define and structure the data and information used in service management, such as configuration items, incidents, problems, changes, etc. However, an information model is not a technique to resolve complex incidents, but rather a way to organize and manage the information.

Therefore, the best approach or technique to resolve the situation described in the question is swarming.