Advanced RSS combiner / website filter or script

I'm almost in desperate need of a website that can combine and filter RSS feeds (unique filters for individual sources would be excellent, but not mandatory) in a single RSS feed that, of course, needs to be updated when any of the sources of the same updates Paid or free does not matter. There is no problem for me to buy a script of this type and keep it myself, if any of you know. You must return the filtered and combined feed as a link, not a downloadable .xml file or anything like that.

I tried a …

Advanced RSS combiner / website filter or script