The Three Lions head coach takes his team to Lithuania and Moldova in September as they bring their qualifying group fixtures to a close.
England have already secured top spot in the group and are therefore assured of a play-off spot in October, when the group winners are paired up to decide which nations head to Czech Republic for the finals next summer.
And Southgate says he’s happy with the depth of his group, with the players who served him so well last season and those who travelled to the Toulon Tournament earlier this summer.
"I think we’ve got quite a settled group now, which is the nucleus of the players from the qualifiers to date and then some of the boys who came in this summer and added to that," explained Southgate.
"It’s not an easy squad to pick now as we have got real competition for places, but the mentality and commitment to play for their country is really important moving forward.
"When I look at the teams which were successful in Brazil this summer, it was clear that the teams who had been on the road together for a long time had a great spirit.
"There’s that element of spirit in this group and, secondly, I’m only really interested in working with the players who want to be here with the very best and play for us.
"Our job in the junior development teams is to prepare people who are ready to go and perform for Roy [Hodgson] and I think that’s crucial, so their mentality is just as important as their ability."
“I’m only really interested in working with the players who want to be here.”
Southgate will name his squad for the double-header in eastern Europe on 28 August, the same day that Hodgson selects his group for the games with Norway at Wembley and the Euro 2016 qualifier in Switzerland.
With the likes of John Stones, Raheem Sterling and Jon Flanagan being involved with the senior squad during the summer, Southgate may have to plan without some of his eligible players.
But Southgate knows he has plenty of other options to call upon, with the new season now underway and players back in action with their clubs to build on last year’s progress.
"I need to talk to Roy about where he sees some of the squad and that will be done over the next week or so," he revealed.
"But it won’t just be about who has done well in pre-season, it’s about how people have done over the year just gone and we’re now looking forward to the next couple of months."