Display default value in picklist based on the value in another field

Is there any way to display a default value in a picklist on service request create based on the value the user selects in the request type field. I know that cascading pick lists allow me to filter options from one picklist to another but if I use this functionality the second picklist is by default blank. What I want is the default value that is displayed in picklist two to be driven by the value that the user selects in the request type field.