Deaggregator should do the trick. It will create a feature per part.
Can you post your workspace, or at least a screenshot of it? I'm unsure in your images which is the Base and which is the Candidate, and which is supplying the group-by attribute in the Dissolver. But whatever way around I try it, I can't get the same result. If there is a common attribute, then all of the features get dissolved. If there is no common attribute, then no features get dissolved - which is your result, but it's because no attributes match.
So it would be really useful to see your workspace because I think there must be something else happening. But one other important question: how should FME know which part of A to dissolve? Is it because it is the smaller part?
Can you post your workspace, or at least a screenshot of it? I'm unsure in your images which is the Base and which is the Candidate, and which is supplying the group-by attribute in the Dissolver. But whatever way around I try it, I can't get the same result. If there is a common attribute, then all of the features get dissolved. If there is no common attribute, then no features get dissolved - which is your result, but it's because no attributes match.
So it would be really useful to see your workspace because I think there must be something else happening. But one other important question: how should FME know which part of A to dissolve? Is it because it is the smaller part?
Hi @mark2atsafe,
Below a screenshot of the workspace. About last question, yes I'm giving the smaller polygons as the base.
Thanks,