Hi Airtable community

I am looking to create a field that updates based on the entry history of another a field. For example, imagine I had two fields “A” and “B”, and “A” is a multiple select field and “B” is the field that I would like to create. It would function like this:

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  Field A contains multiple select value “X” and if I change this to “Y” then I would like Field B to show “X”.

  
  


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  If I then change Field A from multiple select value “Y” to “Z”, I would then like Field B to show “Y”.

  
  

To provide some more context, I’m looking to solve this so that I can send a weekly update email that shows how a field changed during the period.

I’d really appreciate some help