How can you create a combination scope/trait declarator in Raku?

Let's get straight to the point. I want to create a declarator, let's call it testable, that is the combination of our and is export, so that instead of writing

our $foo is export;

we would simply write

testable $foo;

I'm pretty sure something can be done through the metamodel, but I'm not sure this precise thing (scope and trait) can be done or, for that matter, how.