Hey,
that's possible, I hope I understood correctly. This is how I would do it:
In your Excel file, make sure you have a "real" table. (Insert -> Table). In my example, it's called Table1 and it has a row called E-Mail and one called RespondedAt. The Excel is saved in my OneDrive and I saved it as Flow_EmailResponses.xlsx.
In my flow, I then use the action List rows present in a table at the top to get all rows.
Add an Apply to each action to loop the rows. In the * Select an output from previous steps field enter the Dynamic content value from the Excel action.
Inside the Apply to each, add a Condition action to check the E-Mail Address from the trigger (From) with the E-Mail row value in the Excel table.
In the If yes section, you don't do anything because in that case, it found the E-Mail address in the file.
In the If no section you can add your logic / reply.
At the end of the If no section, use the Add a row into a table action to add the E-Mail address and maybe a timestamp to the Excel file.
Next time this person sends you an E-Mail, the flow will go to the If yes section, because the E-Mail address is in the File.
cheers
