How to combine meshes in 4.15.1 ?

I am trying to import a FBX model to ue4 but the engine allways splits it to small parts,eventhough all parts are in one group. I know that in earlier versions was Combine meshes to fix this, but I cant find any similar button in the new version.
I´ve check the model in few other programs and its ok, just unreal does that. Any solution? I would be glad for every reply :slight_smile: