CRM Set Up - Special Application

Any suggestions from CRM Pros: I have a medical group managing patients for large employers. So far I'm using CRM to track biometric screenings (cholesterol, blood pressure, etc). The tool was invaluable in tracking and reaching out to patients for our first campaign. I'd like to use CRM to do clinical task management, tickler for future patient events as well. In addition, I'd like to apply this same process to another client. So.... Is there a way to separate the data (client 1 vs client 2)? Has anyone seen a similar application and can lend advise on setup? Thanks for any and all suggestions.