Perforce QAC Projects can have multiple configurations. For more information, see "Multiple Configurations with QA·GUI" in the Perforce QAC manual.
Within the Perforce QAC Eclipse, there is a drop-down list immediately to the right of the GUI Settings icon on the QAC perspective's main toolbar when a project is activated. You can use this drop-down list to select a different configuration for the project. You can add or remove project configurations, or change the default configuration, by selecting the "Configuration Manager..." entry, which will launch the Configuration Manager. You can read more about this in the "Configuration Manager" section of the Perforce QAC manual.