Multiple Targets

I have a need for a build system that operates like this:

a.prm b.prm : prerequisite
      commonbuildrule

However, I've found that gnumake,

[yates@dsp sim]$ make --version
GNU Make 3.80
Copyright (C) 2002  Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.

wants to execute the build rule for each of a.prm and b.prm. However,
I don't want this to happen. Not only is this a want, but it is a
need, since the build rule takes several minutes to execute (and
in my actual situation, there are many targets, not just two).

Is there a way to accomplish my goals using make?

--Randy