Hope you are doing well.
I manage the product feed system here at buy.at
The matching of products could be considered the holy grail of product feeds As time goes on, more and more merchants are adding UPC/EAN/MPN data as the importance of this data becomes clearer and clearer.
There are a variety of ways to match the products without this data but Im afraid that you'll need to do some manual work to get the matches as you wish. Some people do SQL "LIKE" matches (MySQL :: MySQL 5.0 Reference Manual :: 11.4.1 String Comparison Functions) on the product names. Others will record the EAN from other feeds and match it up to products in feeds that do not have the EAN data.
We've developed a guide which walks you through the integration of a product feed into your website using PHP. Section 7 details how to filter feeds by category - this is especially useful if you work in niche sites (e.g. you only sell CDs).
I hope that gives you a starting point.