If we want to use any addition information details received in the event/Alert from integration for ITOM Event Management alert correlation rule than we can use the tag based alert clustering.

For that we have to Enable the Plugin Tag Based Alert Clustering Engine (sn_em_tbac).

Once we enable the plugin we will have to create Tag Based Alert Clustering Definition (sn_em_tbac_alert_clustering_definitions) and than under that we have to create the Tag Based Alert Clustering Tag (sn_em_tbac_alert_clustering_tags). No coding is required on this approach on the other hand if we use the Rule based alert correlation than we have to create a rule which may require scripting based on the requirement.

For More Info: https://docs.servicenow.com/en-US/bundle/utah-it-operations-management/page/product/event-management...