processor affinity on smp systems for whole processes

Is it possible on a SMP system (QNX 6.3 on dual Xeon) to bind a whole
process with all its threads to a certain cpu ? For a single thread this
works by calling
“ThreadCtl(_NTO_TCTL_RUNMASK, (int)runmask)” from within the thread. But
what to do, if one wants to run a given binary (like the system service
“io-net”) on only one cpu ?