One request first and only after continue with all the users

Hello. I need to obtain some ID and then run actual test with this ID as a parameter. My idea was to run one request before anything else, wait for response, save ID to session and then proceed with all other requests. I know you can run two scenarios like that:

users.inject(rampUsers(10) over (10 seconds)),
admins.inject(rampUsers(2) over (10 seconds))

But as far as I understand this will run simultaneously while I need first request to complete before anything else. Other option I thought about was to wait with other requests with .pause(N) but I’d like my test to be deterministic. It is better to wait until first request completes than just assume it would not take longer than N. Is there any option to achieve that? Thanks.