[Groff] replacement for col

[walter harms]

hi list,
i run into a problem that may be solved by others already.

I show a groff file as latin1, that worked fine. i had some ^H but that where 
filtered by "tr"
no problem. But i added some boldface to the text and i got something like that 
N^HNi^Hic^Hch^Hht^Ht.
No real surprise i know that "col" could handle that. Unfortunately the current 
version (util-linux-2.21.2)
stumble over some umlauts in the text (older version also).

Does someone have an sed statement that replaces col ?
Is there an easy way to tell groff to avoid N^HN for bold ?

re,
 wh