The only way that I know is to dynamically *create* the individuals from B in the context of onto_A:
I implemented a minimal example:
https://github.com/cknoll/demo-material/blob/main/expertise_system/copy_individuals.ipynbIt also shows how to use separate worlds to keep both ontologies apart. However it might be necessary to copy more data than just the comments.
Let me know, if you find a better solution.
Best,
Carsten.