System call from R causes loss of cursor control

Hi All, I am using R to simulate protocol decision making and repeatedly call NONMEM - via a system call - to perform the simulation. The problem with this is that every time the system call is executed, the dos window pops up and cursor control is taken from whatever else that I am working on - beyond annoying! I am using Windows. Does anyone know how to prevent this? I saw in the archives that Mark Sale (I believe) asked this question many years ago, but it did not appear that a satisfactory answer was returned. Thanks in advance, Dave