Ability to send new hire communication on day 0 (first day) with MS Teams

Currently, the earliest option to send a communication to a new hire is Day 1. We would like to be able to send a communication to users on their first day (Day 0) to welcome them from the bot and provide helpful resources. Ideally, this message would be waiting for the new hire on the day that they join, so even if it went out earlier that would be fine as they would see it when they log onto Teams for the first time.