I have seen a few questions about when using load tests how to get a certain number of users executing one set of tests and another set of users executing another set of tests.  For example, suppose your web site is supporting a sales organization.  You will likely have a certain set of pages that the sales managers will hit and another set of pages that the people in the field use.  You also likely have many more sales people in the field than managers.    Here is how I would go about designing a load test for this scenario.

1)      First create the web tests that will be used by the different groups.

2)      Next create a load test.

3)      In the load test wizard, change the name of the scenario to Managers and click next

4)      For the load pattern, select constant and then select the # of managers you have.

5)      For the test mix, select the tests which will be executed by the managers and set the appropriate percentages.

6)      Select the browser mix and network mix for the manager group.

7)      Up to this point all the settings have been specific to the manger group.  The last 2 panes for Counter Sets and Run Settings apply to the entire test.  Fill these out with the information appropriate for your test and click Finish on the load test.

8)      Now you will be back in the editor.  Right click on the Scenarios node and select Add Scenario.  This will launch the Add Scenario wizard which has the same set of scenario specific panes as the load test wizard.  Go through each pane and set the information for the sales field this time.

9)      When you are done filling this out, click finish.  The load test editor will now display 2 scenarios which will be executed for your load test.  When the load test runs, it will execute all the scenarios listed in the load test.

Using multiple scenarios allows you to model different users groups within 1 load test.  It also lets you customize how each group will execute.