I guess there’s no such feature in postman as to run concurrent tests.
If I were you, I would consider Apache jMeter, which is used exactly for such scenarios.
Regarding Postman, the only thing that could more or less meet your needs is – Postman Runner.
There you can specify the details:
- number of iterations,
- upload CSV file with data for different test runs, etc.
The runs won’t be concurrent, only consecutive.
Hope that helps. But do consider jMeter (you’ll love it).