Using concerns

In addition, here is the code I used for the solution Chris suggested, for anyone interested.

# /models/concerns/location_validations.rb
module LocationValidations
  extend ActiveSupport::Concern

  included do
    validates :name,    presence: true
    validates :address, presence: true
    validates :state,   presence: true
    validates :zipcode, presence: true
    validates :country, presence: true
  end
end
# models/restaurant.rb
class Restaurant < ApplicationRecord
  has_many :branches
  has_and_belongs_to_many :users
  validates :phone, presence: true
  validates :email, presence: true
  include LocationValidations
end
# models/branch.rb
class Branch < ApplicationRecord
  belongs_to :restaurant
  validates :resaurant_id, presence: true
  include LocationValidations
end