Pipeline Group Administrators in GoCD can add, remove and edit pipelines in their respective pipeline groups. They can do these operations via the UI as well by editing the config XML of the pipeline group.
The administration page for a pipeline group administrator looks as follows. The controls on the "Pipelines" tab allows her to edit, clone, delete and move any pipeline.
The tab "Config XML" shows the XML snippets of each pipeline group. The user can toggle between different pipeline groups and view/edit them one at a time.