Maximum Throughput Triggers: 10.000 to 50.000. How about lower than 10.000?

From the docs:

Before increasing the maximum throughput, consider whether one or more of your triggers are calling a rate-limited external API. Increasing the trigger rate might result in exceeding those limits.

I have an external API that is limited to way less than 10.000 concurrent requests.

Any ideas how to create a trigger/function that is limited to say 25 concurrent processes?