You can do this with a custom Visual Build launcher program. You will launch the builds with your program and then the program will run a post build routine at the end. This can be another Visual Build project or custom code in your program.
To get started see the sample program they provide in the samples folder: C:\Program Files (x86)\VisBuildPro8\Samples\VisBuildPro\BuildLauncher
Another option is to use Global Subroutine Steps to implement your post build steps and then call that routine at the end of each build. This will require that you modify each build but only enough to call the global steps. The global steps will live in another .bld file that will need to accessible to each of the builds. It saves the global steps in VisBuildPro.steps in the configured path under the Applications options.