I have a Question: Can we change the Service SLA based on Field Values in Service Request?

Scenario: for Example- I have a Service Category "Business Application" and i that category i have a service named " Account Creation". while defining this service, i have  defined a SLA ( for Example- 4 Hours).

      I have also a additional field in this service called "Module" which is  a picklist containing different modules of business application say - Collection, Sales, CRM Etc. 

      So, My requirement is that when the user makes a service request by clicking on the service " Account Creation" and he changes the module say Sales then the SLA should be 5 hours and if users

                                      selects CRM Module then SLA should be 3 hours and if the Collection module is selected then it should be 4 hours.

How is this Possible ???? because SLA are fixed for each serivce at the time of defining the servie? is there a way to achieve this?