Help please!

I have a excel spreadsheet which needs some automatic fills

For example in column A I have the following list of names
John
Jo
Jack
James
Peter
Fred
Frank
Sandy

In Column B next to those names I have a drop down list which displays choices next to the names - “yes” or “no”

What I want a formula for is .....if John is selected as “yes” his brother Fred and sister Sandy will also be automatically populated with “yes” from the drop down menu too. If John is “no” I
also want Fred and sandy to be “no” too.

I am lost...

I am a novice so please be kind!!
Thanks!