Esta regra redirecionará a solicitação de entrada ESPECÍFICA para um URL específico:
<system.webServer>
<rewrite>
<rules>
<rule name="Redirect Specific Page" stopProcessing="true">
<match url="^blog/post/5$" />
<action type="Redirect" url="http://other.domainxyz.com/site/5" />
</rule>
</rules>
</rewrite>
</system.webServer>
UPDATE: Eu os juntei - basta atualizá-lo com URLs reais:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<rewrite>
<rules>
<rule name="home" stopProcessing="true">
<match url="^$" />
<action type="Redirect" url="http://yojimbo87.github.com/" />
</rule>
<rule name="about" stopProcessing="true">
<match url="^Blog/About$" />
<action type="Redirect" url="http://yojimbo87.github.com/about/about.html" />
</rule>
<rule name="Redirect Specific Page" stopProcessing="true">
<match url="^blog/post/5$" />
<action type="Redirect" url="http://other.domainxyz.com/site/5" />
</rule>
</rules>
</rewrite>
</system.webServer>
</configuration>