Export multiple meshes to one FBX...?

Hello,

So my team made a mistake when putting our level together. Long story short: we’re pushing 150k-200k tris because we duplicated the same mesh multiple times and added it piece-by-piece, but because it’s for mobile, we need to make it so these multiple meshes (which all use the same material) are a single mesh that we can position in the same place.

We have the option of taking the terrain and putting it into Max, then duplicating the tremendously-confusing multiple mesh pieces so they form one long “border” around the terrain, or we can try to export from the Unity level the meshes as one FBX file.

The question is: is it possible to take in Unity multiple meshes, select all of them, and then somehow export them as an FBX so when we import it, it’s just 1 mesh instead of 100+ meshes? Or do I have to have my modeler try to create this border in Max by multiplying the mesh like we did in the level, and just exporting it as one single FBX?

Just trying to make things easier.

There are some tools in the assetstore that can merge meshes