subscribe point clouds to octomap

edit

I wrote a node which listen to topic 'rgbdslam/batch_clouds' from 'rgbdslam' package and edit it to publish the required points clouds as topic 'new_batch_clouds'. Now, I need to use 'octomap' to save both point clouds as map. And both has common 'tf' from package 'rgbdslam'.

I tried to make the node 'octomap_server' to subscribe the topic 'new_batch_clouds'. From seeing the codes, I think a topic named 'cloud_in' is subscribed for point clouds. In normal procedure, I don't understand how 'rgbdslam/batch_clouds' would be subscribed by 'octomap_server'

So, now I need two maps. One from the topic 'rgbdslam/batch_clouds', that is done usually. Then, I need another map using 'new_batch_clouds' from the new node and 'tf' from rgbdslam package'. How to make it?

Thanks in advance, for the suggestions.