What is the best email address format for people with the same first and last name?

The larger the organisation (for example a company or educational institution), the more likely that there will be two people with the same name.

Typically, email addresses are formatted firstname.lastname@company.com

What should the email address format be to minimise the risk of emailing the wrong person when you have two people with the same name?

I have seen:

firstname.middleinitial(s).lastname@company.com

firstname.number.lastname@company.com

initials.lastname@company.com

randomstring@company.com

Edit: the other consideration is that the format should work for people both inside and outside the company.

People working in the same company have access to the email directory and may know the person's location or department, but someone on the outside would not.

Edit 2: this is also a common issue for domains that cycle through users on a regular basis, for example universities/colleges where a typical user may only use the email for 3 or 4 years, then graduate/leave. If you choose not to recycle emails, there is a potentially unlimited pool of people with similar names joining/leaving every year.