ServiceNow ServiceDesk Connector for Incident Request

I am facing an issue with servicenow assignment group. it is works fine when provisioning plan contains single account request and assignment group is getting updated based on the custom mapping file values which is configured in plan initializer rule. But whenever the provisioning plan contains more than one account request for servicenow integration, same assignment group is assigned to all the applications. does anyone came across similar situation like this?. Suggestions or inputs or any code snippets to resolve this issue will be really helpful.