Access query complete data

I need your help with completing data in a Access database. We have a database with multiple rows with records that are incomplete. The incomplete data we have in a Excel document.

For example, we have in Access column A, B, C, D, E, F, G, H.
Column A in Access matches the Field in Excel.
The situation is that in certain rows, records of column E, F, G, are missing.
In others B, C, D. In some cases all except A, G missing.

What are the options to complete the data?

I thought of something, a query or script or something better, that can do the following:

1st find matching unique record (from a certain Column) between a Access table & a Excel sheet.
2nd, Based on that then search horizontally in the Access table for blank records.  
3rd, Once found blank records in Access take it's field-/column name then find it in the Excel sheet,
4th, Once found check if that cell is blank.
5th, if blank go to step 1 for other record.
6th, if NOT blank copy cell value to record in Access table.
7th repeat process