Transfer control from one PHP file to another PHP file

Hi, I'm a new to PHP. I'd like to know if there's a way to transfer control from one PHP file to another PHP file within a frame on a Web page. I want to be able to have independent pages with related functionality "call" each other "with no return". I've poured over the documentation and I've already discovered header(), require() and include(). header() requires strict control over output to the browser and there doesn't seem to be a way to make it redirect frames anyway. The other two functions seem to be meant for importing a function or a group of functions, not an entire, fully grown page. I just can't believe that such an intelligently designed language expects the code for an entire Web site to be contained in just one file. If what I'm asking isn't possible to do, is there at least a way to abort all the accumulated output to the browser at a given point in the script? I imagine that many of you have heard similar questions from novices in the past. I apologize if that's the case. Any help will be greatly appreciated.