Hey Ranok,
-
Maya doesnt have smoothing groups. The big suggestion i would make for you model is to chamfer the edges a bit.
- YouTube -
When you are ready to export you simply export your scene (or selected object) as an .FBX file, unreal will triangulate your Geo and gets it right 90% of the time. If you noticed any errors caused by bad Triangulation you can go back and manualy fix it. But with a structural model like you have there shouldn’t be any issues