General Load test Question

Hello-

I'm exploring the load testing feature and am running into some issues.  The application that I'm testing requires unique naming for all items created per each user so I started with a functional test that has a excel data source.  My intention is to first test that multiple users can complete the same action at the same time and then introduce concurrency.  I've created my load test with one user profile (from a functional test) that would essentially log in to our application and create a unique object.  What I don't see is how to handle the issues of uniqueness when the virtual users are increased i.e. 10 virtual users running a test that logs in and creates a unique object with the same user account and the same name for the unique object.  I didn't see anything in the video's or the help to address this.

I then created two user profiles that are from functional tests that do the same thing (with different user accounts), have set the virtual users = 2, set the Start test with = 2, and split the workload 50/50.  When I run this test, only the steps from the first profile will complete (I did not clean up the data as part of the test to ensure what is running).  I may not be handling this correctly but I can't see how to assign virtual users to each profile.  My assumption was that if I had two profiles with 2 virtual users that started at the same time and that have the same amount of resources, they would be run at the same time.

Just to re-iterate:

1- How can I test uniqueness within my application while ensuring that the test is working correctly?
2- How can I allocate virtual users to specific profiles?
3- What steps need to be taken to ensure that 2 profiles will be run at the same time?

Thanks, Jon