There might be a scenario where you have to add multiple gulp file for a project. example: CMS with multiple sites in it or multiple theme for single project.
You could use npm-chug, since it’s black listed you can use other techniques. If you don’t want to compile all resources just execute custom gulp file by name
gulp --gulpfile gulp-project-file-name.js gulp --gulpfile gulp-other-project-file-name.js