Posting data through PHP scripts

I have been thinking about a thing. If I have a PHP script (a) which receives some data by a POST method only -- GET method is track to not be accepted --, and if I have another PHP script (b) that takes initial input from the user's browser... Well, the question is: how can I, in the script "b", take the input data and post it to script "a" and receive its response, following by processing it and giving back the response to the browser? The user wouldn't see the action of script "a" in any way. To the user, only script "b" would exist. I think I can do this by using Delphi, but in PHP this task seens to be a nightmare. browser ==input==> b ==post==> a... ...a ==response==> b ==response==> browser Is this possible with PHP 3 or later?