Hi gmajay,
Hoping you are doing well, May you please share your script with us?
What you want I believe is to parametrize 2 users and every user should update only 5 records, one by one:
User 1 --> Update first 5 records.
User 2 --> Update the remaining 5 records.
Effectively, you can parametrize the Use by Username or another valid property to be parameterized. On Parameter List you may need to know that there are three ways to "select new row" in case that you want to use the first user and then the second user. For instance, if you will be selecting "Sequential" mode it is because you need to run the user1 first and then on the next iteration it will be running the user2.
There are other such as: Randommode and Unique. With the Random, it depends on how many iterations you want to run and thus it will give a random choise. Lastly the Unique will displayed only a unique result, user1 and user 2 for the 10 attempts to update the records.
I would like to take a look of the script and see if I can provide an advice.
Kind Regards,