Running simultaneous load tests

Can you please give me some instruction on designing a load test that executes multiple webservices simultaneously.  It appears that each load test is defined as part of each test case.  Rather than running each load test individually, I want to  design a load test that executes a mixture of activity with multiple webservices.  I can't find any facility in the UI for this other than manually starting each load test.  I noticed that there is command line facility (loadtestrunner.bat).  Can this be used to run multiple test simultaneously?