writing a big band score

I've been using Sibelius for years but decided to try Musescore 4.1. It is pretty easy to use but there is something I cannot do which i easily do with Sibelius. And that is writing the whole score in one key without assigning each instrument its own key. It is a very useful thing and I cannot find it in Musescore. In other words, if i write a score in, suppose, G major, I want all the instruments to be in the same key until I finish the score and transpose. Will appreciate if somebody tells me how to do that.