Answer by skladany for MailChimp: How to use conditional logic with RSS feeds

Well, this question is from ages ago, but I had a similar problem and figured out a (really hacky) work-around...

Assumptions:

1. You're using a (very) custom RSS feed2. You're overriding the default RSS tags with custom content

In my use case, I'm using the <category> RSS tag, which MailChimp reads in via the *FEEDITEM:CATEGORY* merge tag. I'm using this as a subheading for my RSS feed, instead.

If that subheading is filled out in the admin (that is, whatever admin system you're using to spit out the RSS feed), I want to include it in the feed -- but I also need to add in more html for the email template. The solution is including the required html in the RSS feed. (Like I said -- hacky.)

Shockingly, this works. Mailchimp dutifully pulls in all the html/css.

The RSS feed (vastily simplied here) looks something like this:

<channel><item><category><![CDATA[ <table><td><tr><div class="example">Sub Headline</div></tr></td> ]]></category></item><channel>

If that field is not set in my custom admin, then no <category> tags at all are outputted, and MailChimp simply ignores that merge tag.

So basically, any email HTML code that you want to display only if the merge tag is valid, should show up in the feed itself.

Definitely not ideal, but it works.

YMMV...