[rules-users] A design decision to use Guvnor

My requirement is as below: We need to give end users to provide us with some conditions, One of example rule would be: They can say something like when the client id is XYZ(could be a complex condition here) then consider I need to pay taxes in AB,CD states. As we have different end users, we can have these rules per end user. And when we get a web service call, based on the end user we need to pull all these rules and then apply the rules(basically all these rules do a transformation on the incoming request) I need to a design for this requirement: At first I thought I can build a UI and db to save all these rules. But I realised that it would really take a long time. I found Guvnor as a web application, with which we can provide a UI and these rules will be saved in db. The confusion I have now is: Can I tweak the Guvnor source code(locally) to make these rules saved per end user? Is it doable? Any suggestions, for the design are welcome.