How to remove the relation between a file and a .deb package

["M. Frey" <m.frey@avelon-cetex.com>]

Hi,

I'm using my own Debian .deb-packages for managing software updates on a 
small numbers of embedded computers. So this question is about creating 
my own .deb Packages. I hope you can help me, even if I'm not an 
official debian package maintainer.

I got the Package A with the version 1.0 and 2.0. From version 2.0 on 
it's not necessary to keep track of the file fileB.txt. But I want to 
keep fileB.txt on the target system anyway.

Package A Ver. 1.0:
 - fileA.txt
 - fileB.txt

Package A Ver. 2.0:
 - fileA.txt

If I install the new package A. DPKG will of course remove fileB.txt.

How can I prevent dpkg to remove fileB.txt? In fact, dpkg should simply 
forget that fileB.txt was ever part of Package A!

Of course, I could manipulate the dpkg file list, somewhere in the dpkg 
cache (file system). But how can I achieve the same effect within a 
package -> without manual manipulation on the target system?

Is there any key word in the control file? Or is there a special file, 
which lists "dependencies to delete"?

What happens if the same file is contained in two packages and one of 
them gets removed?

thanks for any suggestions.

maus