request: rez-build flagged directory

It would be possible to rez-build a whole pile of stuff all at once, efficiently, with a flag that effectively changes directory in to a package dir prior to package build.
So given an unbuilt package directory with some packages, one could run a series of chained build commands. Example hypothetical usage;
rez-build --build-path path/to/package; rez-build --build-path path/to/otherPackage

It's possible to work around that with a bunch of cd commands between commands, but supporting in the box as a convenience would be nice. Terminology and wording/flags named at your discretion.

Start at the rez-build command entry point and inspect how package directories and build paths are currently handled. Reproduce the chained package-build example from the issue, then define the flag behavior and verify that consecutive commands can build each package without intervening cd commands.

Written by the indexing model from the issue text.