I'm only familiar with the software that I'm using. For pictures and other media exhibits--or objects, if you will-- most of them are external, so the path is already set to whatever is being referenced. The few internal exhibits might be a problem. As for sources, you merge them; whatever citations were referencing the two or more different sources will now reference one. it simply transfers all the cites from one source to another surviving source. All you need to do is connect the people in the dataset, by marriage, birth or otherwise.