This is possible. You would have to use the same database for all your content. You would typically separate the different parts/sites by using different folders, sections and so on. The point is that everything would be in the same database. You could set up the following siteaccesses:
-Health (using design "health" and DB "my_database")
-Hipertension (using design "hipertension" and DB "my_database") -Admin (using design "admin" and DB "my_database")
In addition, all siteaccesses would have to use the same var directory so that images & stuff are available for all of them. Use the host matching feature (configurable from site.ini) to set up the access rules: