Select -> Same Material -> Currently Visible

Hello guys,
i am trying to optimize a scene and merge actors. I am having the problem that i have a few hundred objects spreaded across the map and i like to merge those that are in the same place into a single object. Currently when i choose Select All By Material it will select all objects but also those that are not visible. It would be awesome if the editor has a few more selection objects based on the objects that are currently visible.

E.g. Select -> Select All with same Material -> Only currently visible.

That would make things a lot easier.