You can't do that in a single file. Once you exclude children of root item you cannot, later on, include it back.
You separate files for this, e.g.:
<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
<sitecore>
<unicorn>
<configurations>
<configuration name="Content.xxx.yyy" description="Content.xxx.yyy" dependencies="...">
<targetDataStore physicalRootPath="..." type="Rainbow.Storage.SerializationFileSystemDataStore, Rainbow" useDataCache="false" singleInstance="true" />
<predicate type="Unicorn.Predicates.SerializationPresetPredicate, Unicorn" singleInstance="true">
<include name="YYY" database="master" path="/sitecore/content/xxx/yyy" />
</predicate>
</configuration>
</configurations>
</unicorn>
</sitecore>
</configuration>
and the second one:
<?xml version="1.0" encoding="utf-8" ?>
<configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
<sitecore>
<unicorn>
<configurations>
<configuration name="Content.xxx.Corporate" description="Content.xxx.Corporate" dependencies="...">
<targetDataStore physicalRootPath="..." type="Rainbow.Storage.SerializationFileSystemDataStore, Rainbow" useDataCache="false" singleInstance="true" />
<predicate type="Unicorn.Predicates.SerializationPresetPredicate, Unicorn" singleInstance="true">
<include name="Corporate" database="master" path="/sitecore/content/xxx/yyy/Corporate" />
</predicate>
</configuration>
</configurations>
</unicorn>
</sitecore>
</configuration>
Remember about setting up proper dependencies, so that you won't end up de-serializing child items when root item isn't there.