How to extend the dependencies of a reused plugin ?

Hello,

I have two maven plugins A and B.

When used separated I can extend the dependencies of A using this:

<plugin>
<artifactId>org.A</artifactId>
<dependencies>
<dependency>
<artifactId>anDependency</artifactId>
</dependency>
</dependencies>
</plugin>

Now I have the plugin B that defines a custom lifecycle and there I
added a reference to a goal of plugin A in the install phase.

question is: how can I extend the plugin A dependencies in this case ?
(note that final user should declares only the plugin B in its pom)

thanks a lot

regards,

Cristiano