If you want to apply a set of rules to any email coming in to any of your mailboxes, the way you do that is you pick one of your mailboxes to have your "master" rules. Then, in all your other mailboxes, you put just one rule with the "Include" action to include the rule set from your master.
The "Include" action Includes the rules from the mailbox given in the parameter. Rules are
always included, so there can be no Item or Condition. Only one level of
include recursion is permitted. Processing continues with the next rule
in the current mailbox after the include, assuming none of the included
rules delivered the mail.
Therefore, you can both include master rules and have special rules for individual mailboxes. You can also override a
master rule by listing other rules before the Include.