Setting affinity for third party applications that create threads

Hope this is the correct forum to ask this question.

We can use KMP_AFFINITY and associated infrastructure to set affinity for threads spawned by applications we've developed. And we can use numactl to bind a single-process third-party application to a core. What's available to bind threads spawned by a third-party process to a particular core? We can set what's effectively a CPU set using numactl for a third-party application. The threads spawned by a third-party process will stay within this CPU set but appear to move around between cores. I would be grateful for pointers on how we can bind threads spawned by a third-party process to a particular core

Thanks

David