Trying to expand a json array into multiple columns

I am trying to set up an ingestion from an event hub to a KQL database.  The difficulty in doing this is that there is a payload field that is a few levels down.  I am trying to do this via the UI using an Event Processor to do this and I can go most of the way there.  I can get to the point where I have a column with the payload:

Here is a simple example of that column:  [{"name":"itemA", "section":"34", "key":"1234"}]

I could use "expand" here, but this breaks out the payload into 3 rows.  The problem with this is that the "key" only exists in one of the rows and I have no way to tie it back to the other entries.  Is there another option using Event Processor?  I am trying to avoid doing this in code.