Showing only episodes with particular tag (not other posts)

So I just started using tags on my podcast episodes. It seems that the podcast tag taxonomy is shared with regular posts. Is there a way to only show episodes with tag foo and not show all the posts tagged foo?

This is my use case… I have what you could call “sub-series” in my podcast. So a particular topic that is covered in detail sequentially over a number of (non-consecutive) episodes. I’d love a simple URL that would display these as an archive page, preferably in forward chronological order.

Because the podcast is part of a website, there could be other posts on the site with the same topic that I would not want to appear in the sub-series archive.

My work around will be to create a tag called foo-series, but if there was another way that would be great. I thought there might be something built in to wordpress to only display an archive of a tag for a custom post type (which I believe is what the episodes are) but I can’t figure that out.

Thanks!! Love the plugin.