You can use my XperienceCommunity.WidgetFilter module.
"Add [assembly: RegisterWidgetPermissions] to any widget widget you wish to limit by User type, Role, or Site. If a widget has no RegisterWidgetPermissions attribute, then it will not get filtered out by permission."
You're welcome :-)
PS: You may want to check out the various nuget packages "XperienceCommunity.______" as well as Github.com/KenticoDevTerv /Github.com/WiredViews as Sean and I have put out many tools for free.