Well, it’s up to you. You know your application better than anyone else.
Here is another, even more of a hack, way too do it.
You can make the repeating group a type of text. Then you can do a search for both different dataTypes unique ids. These are both a list of texts so it will allow you to do a merge with. Then, within the repeating group cell, you display the data.
I would suggest having two groups where each collapse when hidden. Only display if the data is not empty. Each group you do a search for the dataType’s unique ID. If it has one, display it, if not, hide it.
Does that make sense? To me, doesn’t seem as efficient, but you can decide. Hope that helps! Let me know if you need me to set up an example for you.
As another alternative, you can take out the event details from each type and make a new data type called event details. Then make that your new dataType that is the same. Just another option I would throw out there. Not sure if that fits in with what you need though, it might just add more complexity than necessary too.