It is possible. How you lost GCP constraints? Can you show here some print screen of it?
What were your steps and alignment settings? Was the “slave” component computed as Unknown for its prior pose?
How was the base component created? How were the GCPs measured?
In your case it should work like:
- Import first set of images and align them
- Import GCPs in correct coordinate system and place them correctly around the images
- Set the prior pose of the images to Unknown or set No for Use camera priors for georeferencing in the alignment settings and align the images again (it also depends how precise the image’s GPS is and you can decide, if you want to keep these positions on)
- Import second part of the images, set their prior pose to unknown and align (in this step you can also measure some of the GCPs over this part of the images, which will help in the alignment process)
- If the components are not aligned you can also used another control point to merge the components
You can consider also this helpful in your case: RealityCapture Help