Hi,
No I'm afraid not. In this case you would need to manually create the materials and re-assign IDs. If it helps, I often use the "Multi Material from Selection" script included in
Rappatools to quickly create msub materials from the segments. Alternatively a manual procedure to create multi-sub objects from segments is as follows:
1. Attach all bridge section into a single mesh. Use the default options, so Max creates the multi-sub object.
2. Detach each element in separate objects.
3. Re-adjust the pivots if necessary.
I hope that helps.
Many thanks,
Paul