tight coupling for related libraries

["Steve M. Robbins" <steven.robbins@videotron.ca>]

Hi,

I'm maintaining a package (gmp) that produces a C library (libgmp) and
a C++ library (libgmpxx).  The latter links against, and depends on
the internals of, the former.  

The libraries go into different binary packages, but since they are so
tightly coupled, I'd like to have the libgmpxx package depend on the
libgmp package with identical version number.  I'd like to use
something like the following for libgmpxx package

    Depends: ${shlibs:Depends}, libgmp3 (= ${Source-Version})

but the dependencies are then

    ... libgmp3, ... libgmp3 (= x.y.z)

and lintian complains about the "duplication".

How do I get a single "libgmp3 (= x.y.z)" dependency?  I don't want
to mess with the shlibs file for libgmp3 itself.

Thanks,
-Steve