Well, unfortunately it's not as simple. We have discussed if include that Forest feature, but has some inconvenients and not all users like it.
For example, material IDs of the source objects must be changed, and that creates problems with some plugins (i.e. with VRayMultiSubTex).
We have some ideas to implement a more efficient method, but could not develop it yet.
But please note there are not restrictions to use multiple materials by yourself. Just create a multi-sub material, and modify the material IDs of your segments properly.
It can be done easily attaching all segments in an unique mesh, get the multi-sub material generated by Max, and then separate the segments to independent objects again.
Basically it's the same same process that does Forest with the automaterial, but making it manually.