add some funtion to one script

I have a script in php that I need add some funtions, **The script create pages by keywords, the content of the pages is taken of the search engines TASK: I want that the script work with "proyects" each proyect will create a subdomine each proyect will have his won keywords, that ones keep store in a [login to view URL] (or like that) the script will make pages with that keywords, once that I up all the keywords that I need, I can programar the script for makes pages each 1, 2, 3, 4, hours, etc. But the horary be aproximate, that mean that if I selection, make one pages each 6 hours, the script will make pages each 5 hours, the next in 5:20, next in 6:00 hrs, the next 6:35hrs, etc . (random the horary). each "proyect" will create a file in formate xml, the one be actualized each time the script make a new page. all other funtiones of the script keep equal. **My english is not so good so, if something is not clear please ask.