Webhelp Output Folder Structure

This is more of a question than an issue.

When I generate webhelp from a FrameMaker-integrated RoboHelp project, RoboHelp always adds a folder to the output to match the name of the FrameMaker book in the Project Manager/Project Files folder.

Example:

My FM book is called apiusersguide.book. After bringing the content into RoboHelp, the parent folder (to match the book name) is apiusersguide. When I generate the webhelp, I want the output to be in a folder structure that looks like this:

apiguide\
apiguide.htm (webhelp startup file)
chapter1\topics.htm
chapter2\topics.htm

and so on. The output I want is apiguide\chapter\topic.htm.

However, RH ALWAYS adds the book name to the top level, even if I omit it in the Webhelp Output Folder field when I generate. So the folder structure ends up looking like this:

apiusersguide\ (name of the FM book and top level RH folder)
apiguide.htm (webhelp startup file)
apiguide\
chapter1\topics.htm
chapter2\topics.htm

and so on. The output I GET is apiusersguide\apiguide\chapter\topic.htm.

I've experimented with a variety of different FM book names and output folder names and RH ALWAYS inserts that top level folder automatically. Is there any way to NOT generate the extra top level folder in the output?