No, C # does not have this concept. In this regard, each source file is independent. (And if using directives are in the namespace declaration, they are independent of others, using directives in peer name names declarations too. This is a pretty rare case, although in my experience.)
ReSharper, , . Visual Studio.
EDIT: , , , ( ):
using Foo;
namespace X
{
using Bar;
}
namespace Y
{
using Baz;
}
use.