Content Strategy: Similar but unique content
I would agree with beth's post earlier, use a taxonomy to group all the different content types you are working with.  For example, create a taxonomy vocabulary named "Conference".  For EACH of the content types used to store information about the conference, add a field:
Label: Conference
Type: Term reference
Form element to edit the data: Autocomplete term widget (tagging)

Now, when you are filling in the details using your different content types, tag your content with the conference name.  Later you can filter display of that information by filtering on the taxonomy term.