Southampton join the U's, Cambridge United and Southend United in Checkatrade group.
As in previous seasons, the top two from each group will progress, into the first of the knock-out rounds in the competition.
The format for this year’s competition is much the same as 2017/18, with only a couple of small changes to the Regulations.
Players from EFL clubs who are out on loan in the National League and below are now eligible to feature in the competition, while invited teams have been restricted to fielding two players over the age of twenty one and more than forty first-team appearances.
The first group stage games are currently scheduled to take place in the week beginning September 3rd.