How to cumulate server roles with Datum

DSC
1

I have create one file per role.

  • WebServer.yml
  • FileServer.yml
  • SqlServer.yml
  • ...
How do I declare several roles in the node configuration file? 
Role:
- WebServer
- FileServer
How should I handle the precedence in the datum configuration file, knowing that there is a baseline configuration? 
ResolutionPrecedence:
- AllNodes\$($Node.ComputerName)
- Roles\$($Node.Role)
- Roles\ServerBaseline
Or is this done with the lookup_options parameter?