The regular build process is described in Following the build process.
The modified build process for external projects is a multi-phase build. > ccm project_grouping -thaw "All X/1.0 Integration Testing Projects"
Project hierarchies that contain external projects cannot be completely updated right away because the new products you want to select may not exist until the hierarchy is partially built. (If the products are in a non-writable state before the build, new versions will be checked out. Those new versions need to be selected into the external project after the build is complete.) Portions of the hierarchy need to be updated and built in phases.
To prevent selecting new tasks, clear auto-update on the project grouping after the first update, then set auto-update in the middle of this multi-phase build on the project grouping after the last update. The following example shows you how to do this: