Dear Sir !
As my understand, you wan script can run many threads (5 thread for 5 rss), so each thread can output data.
We have 2 case
1. if you want run via web interface, we can call 5 ajax call, each will read rss and output data to each div container, or write to file
2. if you want run via command line : a mother script will call 5 child script, each child script will process rss and out put data to file.
Since you said output entry as a list in html, so maybe you want list it in html content (case 1), or we can save it to html file.
I can handle all, just need to know what you want. I work with PHP > 9 years, done many project, so you can trust me.
Thanks.