[gentoo-user] concatenate ogg-files...?

Hi,

I have three ogg-files (audio) which I want to concatenate 
in a way, so that as much as possible of the audio quality
will be preserved and the result should be an ogg-file again,
which not only plays ok, because mplayer or what ever simply
skipps over format violations but is of a valid ogg format.

How can I do this ?

Thank you very much in advance for any help!
Best regards,
mcc