I have created 2 web performance tests.

Register User - This would read user detail from csv file and register the user.
Activate user - This would be run after “register user” script and would activate the above registered user by clicking on the activation link from the email

We would like to do this for 1000 Users, with approach that for each user it should read the details of the user from csv file and register that user and click on activation link to activate. For this scenario i want apply load of 5 user and until all 1000 user. Not sure how to achieve this. any help is appreciated.