There's no problem calling pastie.get multiple times
alias pastie.test {
pastie.get http://pastie.org/pastes/9077474
pastie.get http://pastie.org/pastes/9077475
pastie.get http://pastie.org/pastes/9077479
}
The problem is you're using the same global %output variable instead of passing the output to pastie.get when you call it. You can specify a file or folder for output.
/pastie.get url output