code: private static void addDialectsFromVMParameters() {
      	Properties properties = System.getProperties();
      	for (Object key : properties.keySet()) {
      		if (key instanceof String) {
      			String name = (String) key;
      			if (name.startsWith(DATABASE)) {    				
      				String databaseName = properties.getProperty(name);    				
      				int index = name.indexOf("_");
      				if (index > 0) {
      					String suffix = name.substring(index);
      					String dialectClass = properties.getProperty(DIALECT + suffix);    					
      					if (dialectClass != null) {
      						addDialect(databaseName, dialectClass);
      					}
      				}    				
      			}
      		}
      	}
      }
docs: With _<n> we can specify any number of dialects