Softimage Xsi: instances and deformations

I am doing a quick cityscape and need several bridges spanning from one point to another. I did the bridges by modelling one arc and instancing it along the way to keep the scene efficient. I also intended to do something like this with buildings crawling up a ridge, but I didnt expect the problems I am facing now.


Is there a way to deform a number of instanced models by a lattice as if it were a single object ? Right now the individual segments break up when I want the bridge to go up or down....


Instances would really help me out here, the whole scene was started with the idea of "tileable" models. Do I have to go the hard way and script it (like deforming and offsetting the segments with linked parameters or such) ???