Combining default feed and external rss feed

I am trying to present on the frontpage of my site a list that contains both local news items and items from an external rss and display it in a similar manner as the default frontpage feed. How can I do this?

I tried combining a view with an rss display and an external rss feed into a single feed category, which successfully combines them, but I don't seem to have any control over how the Aggregator block formats the display of its items, and its default formatting is pretty minimal.