Serialize portion of parallel make -- Resource limitation not dependency

[HM]

How can I serialize a section of a make file that is resource limited
and not a dependency.

I'm using gmake to run a series of jobs that are interdependent.
Several of the steps use the same underlying resource (single threaded
remote app) to create the needed files. But the actual files are
completely unrealted.

Adding a dummy dependency (which is what I'm currently using) causes a
rerun of steps if one of the files need to be recreated.

After reading and re-reading the info pages, I haven't been able to
see if there is a mechanism to serialize just a section of the make
file.

Any help would be appreciated.
<chaim>