In sitefinity u can show whole widget section for backend users only.
When u creating widget, u need to specify SectionName. For example "CustomMVCBackend "
Then compile and run solution. If u will go to page editor, u will be able to see this section.
U need to go to App_Data\Sitefinity\Configuration\ToolboxesConfig.config and edit it.
Find your section and add attribute tags="backend"
It should looks like that:
Then restart and go to page editor again. Section "CustomMVCBackend" will be not available for frontend pages, for backend pages only