should i use Factory pattern for sending dynamic mails for more than 50 clients

I am having chalice project and using that i am sending mails to the clients. Every client is associated with an organization. Till now i was using same template for all clients but now i need to make changes in the mail template at organization level like every organization demand different things in the mail for their users. Should i use factory design pattern in chalice for solving this problem if organizations are more than 50. I doubtful because for that i have write 50 different classes for each organization Or should I use decorator feature of python which can wrap every function as per the requirement. Please help me with this if you are having clear knowledge of Design pattern.

def userDecoratorMail(func): #passing method as first class function
    def wrapperFunc(appdata):
        if appdata["org_id"] == 5: #checking the condition with client id
            return func(appdata)
        return "Secondary Template"  #return secondary templte.
    return wrapperFunc
        
@userDecoratorMail     
def mail(appdata): # Base method
    return appdata #some mail function will get trigger with appdata information
dict1 = {"user_id":"123","username":"chandresh","org_id":5}

mail(dict1) # calling base method.