queue processing behavior

Hi masters,

I have a question regarding queue prioritization. I have no paramaters in sxmb_adm> configure filter for queue prioritization. Does that mean that XI will process the queues linearly? I mean if I pass a text file A to FTP, then I pass text file B, then text file C, will they be processed according to this order: A, B, C? It's weird because that's not what we're experiencing now. In we05, all SOs / IDOCs of A and B should have been posted hours ago. But in our case, while IDOCs of C is being posted, there are still some IDOCs of A and B in between SOs of C. How can I avoid this? I want XI to process first the text file that was passed first. Please help.