You are meant to do this kind of things in the UV editor of your 3d app.
Every Material on a model you are planning to use in a realtime enviroment such as UE4 has to have a material projection called UVW-Mapping (to speak with C4D terms).
If you are using other projections like cubic, cylindric, sphere etc. they will be turned to UVW mapping at export.
Still i’d always prefer to turn the material projection to UVW before the export.
Step by Step:
Set up your Texture in an apropriate projection.
In this example cubic mapping will do.
I took a Cube with 400x200x20 and used cubic mapping with the coordinates seen in the picture:
https://picload.org/image/wwirwow/wall01_p01.jpg
To get this into a usable UVW map, mark all faces of the mesh, right click on the material and choose assign UV coordinates:
https://picload.org/image/wwirwlr/wall01_p02.jpg
Check the result in UV edit layout.
Currently it’s bigger then the UV canvas, which might lead to errors during import into UE4.
https://picload.org/image/wwirwla/wall01_p03.jpg
First of all, delete the UVs of unseen faces, or delete the geometry of these faces completly.
What you do depends on if these faces might be needed for casting shadows.
https://picload.org/image/wwirwll/wall01_p04.jpg
Next enable snapping and snap the UV island of one wall side to the other one.
https://picload.org/image/wwirwli/wall01_p05.jpg
Then select all faces and fit them to the canvas.
https://picload.org/image/wwirwlw/wall01_p06.jpg
If you want to preview the tiling of the texture, use these parameters.
Pro hint: if you use R17.048 with fbx 6.1 2010, these tiling values will be imported as a TexCoord node, so WYSIWYG.
https://picload.org/image/wwirwcr/wall01_p07.jpg
Instead of tiling you could also use an alternate method and divide the wall in a way that one quad has the size of one tile.
I used 4 segments in x 2 segments in y and 1 in z and then made the cube editable.
The rest works just like in the other example pics 2-5, but instead of fitting the whole thing to the canvas i just stacked the UVs on top of each other.
https://img1.picload.org/image/wwirwca/wall01_p08.jpg
Here’s the example file: