How to transform the pose after map merge

Hi everyone! I am studying on cooperative simultaneous localization and mapping(C-SLAM). I found some tools like [Map Merger Tool](https://github.com/ahhda/Map-Merge-Tool) can help me to merge the maps by using OpenCV. However, how I can transform the pose of each robot and update the map of each robot, so that they can locate themselves and do some cooperative actions in the merged map? Could TF help in this case? In my case, I have 1 laptop and 2 robots(1 indigo, 1 jade) with lidar, occupancy maps are generated using GMapping.