clbuildprogram

hi guys… i would like to know if its possible to run clbuildprogram call in parallel? according to my experiments i see that it can run in parallel in maximum 2 threads. i am not able to compile kernels in parallel… for eg: i have 5 kernels and if i try compile them in 5 different threads, only 2 of them run in parallel and rest takes place after the first 2 compilation is finsihed… can anybody give some insight? thanks…