The IS based SAP adapter have multithreaded RFC listeners.
From the admin UI, where you define your listeners, you can simply select the number of threads, your listener will have.
The listeners use ServerThreads.
Every thread will use the same program-id for the RFC registration.
Eg. If you allocate 10 threads, you will be able to perform 10 simultaneous RFC calls from R/3.
#webMethods#Adapters-and-E-Standards#Integration-Server-and-ESB