Possible to change rules for how email threads are created?

Would it be possible to change the rules for how threads of emails are formed? Currently, it seems a thread will not be created for two (or more) emails that are identical except for the “from” email address that they were sent from. For example, this is not the case in Gmail; Gmail will thread two emails if they have the same subject and body even if the “from” email addresses are different. This functionality may seem odd but would be very useful for my mail system.