Filtering rules to exclude post with certain characteristics

[Clefaria]

Being able to exclude articles in feeds that match certain criteria is the only major feature GreatNews is missing. For example, let's look at this feed:

http://feeds.penny-arcade.com/pa-mainsite?format=xml

I'd like to be able to tell GreatNews to discard/trash posts that start with "News: ". If I could do that, this program would be perfect.

[ktm]

Add a News Watch, make it mark items containing the string "News:" as read.