Partial groupId for Maven Archetype - preventing duplicate groupId in folder structure

Question

I'd like to use

<groupId>com.mycompany.${groupId}</groupId>

In my archetype-generated projects, instead of

<groupId>${groupId}</groupId>

is that possible? It seems to work ok for poms, but for actual files I have

src/main/java/com/mycompany/__groupId__/__rootArtifactId__

file structure, but using the archetype Maven generates them as

src/main/java/__groupId__/com/mycompany/__groupId__/__rootArtifactId__

in the file system. I don't get where the extra groupId is coming from and how can I prevent it.