use of depends, suggests, etc

Hi,

I'm putting together an R package.  In explaining how it works (in the 
Rd files), I want to refer to another package.  The other package is not 
used anywhere in the actual code nor in the examples. So, there is no 
reason to include the other package in the Depends, Suggests, or Imports 
lines of the DESCRIPTION file.  People will be able to use my package 
without actually installing the other package.

However, "R CMD check" warns about "Missing link(s)" when it is checking 
the cross references in the Rd files.

What is the preferred way to make this warning go away?

Thanks in advance,
     Kevin