InDesign XML : styling nested elements

Question

In InDesign, I'm making a document from an imported XML film structured like this:

<?xml version="1.0" encoding="UTF-8"?>
<root xmlns:aid="http://ns.adobe.com/AdobeInDesign/4.0/"
    xmlns:aid5="http://ns.adobe.com/AdobeInDesign/5.0/">
    <item>
        <title>Some title</title>
        <author>An author</author>
        <etc>More fascinating stuff</etc>
    </item>
    <item>
        <title>Self-help best seller</title>
        <author>Anonymous</author>
    </item>
</root>

To style this document, I associate the tag names and paragraph style names of the content tags (title, author, ...). The item tags are repeated containers that enclose the content of each item but have no direct content.

My question: to visually separate the blocks by adding some space after each item, is it possible to apply a style to item in the same way that I do for the "content" elements? I've created a style named item with the desired space after and associated it with the tag, but it seems to have no effect at all.

If that's not possible, what would you suggest to achieve what I want? I could set the space on etc (last tag), but suppose it is not certain to be present on all the items.