Support Group hierarchical routing and default support groups by task workflow

[Lisboa]

Two different topics around the same topic of routing have come up in our organization and looking for perspective from others who have been here or may have solutions for them.

1. Best Practices for establishing L1-L4 Support Group routing
   From a typical operations perspective, how have you implemented ticket routing based on levels of support?
   
   * L0 - Automation/Self-Service
   * L1 - Service Desk (Front Office/Customer Service/Operations Center [event-to-incident])
   * L2 - Tech Support (Mid Office / Support Engineers / Sys Admins)
   * L3 - Subject Matter Experts (App Owners / Architects)
   
   Where I'm going with this is that we want to leverage our Service Desk or NOC as the default Support Group (and therefore Assignment Group) for Service Offerings and other CIs - giving the front line resources the opportunity to address most of the inbound work before passing along work where L1 doesn't have the means or knowledge to resolve.
   
   What are the best practices to ensure L2/L3 is more systematically or automatically known if L1 has to move a ticket along?  Looking to avoid reading through KB articles and simply have the L1 resource intuitively click on an escalate button or be able to pull the Assignment Group group value and know "these are the go-to L2/L3 groups".
   
   
2. Configuring different default Support Groups per ticket workflow
   
   Our investment in ServiceNow spans most modules with the exception of HRSD.  What we are finding is that we want to have different default Support Group (Assignment Group) values depending on which task type is in play (Events, Incidents, Remediation Tasks, Security Incidents etc.)  Certain tasks by default we want to keep to our standard Service Desk or NOC groups, but other times we know out of the gates that things of a more sensitive - we want to ensure that those tasks once initiated go straight to the L2/L3 groups.  We are struggling to determine best practices here so work goes where we want it out of the gates.
   
   What have you and your teams done to ensure more effective distribution of tasks?