prompt gets irritatingly long by following circular softlinks

I have pairs of softlinks that point from one file system to another in
exactly opposite and corresponding directions: "home" and "scratch"

If I cd back and forth multiple times my prompt gets irritatingly long
of the sort:

xxx/yyy/..../scratch/home/scratch/home/scratch/home>

I use this tcsh prompt string: "%S%n@%S%m:%S%~>"

A simple cd `pwd` corrects the prompt to the desired:

xxx/yyy/..../

Is there a smarter workaround so that I always have a "nice" prompt
thats not confused endlessly by circular links?

--
Rahul