You can only do this if the two objects share the same type, and they aren't here.
Note that there's no need for you to use braces on the outer using
, and the code looks cleaner without it:
using (var cmd = new DB2Command(...))
using (var rdr = cmd.ExecuteReader())
{
// Magic super-duper-top-secret-code-here
}
If the objects are both of the same type you can do this:
using(FileStream stream1 = File.Open("", FileMode.Open)
, stream2 = File.Open("", FileMode.Open))
{
}