West of England, who take on the South West on Sunday 16 September, will play a trial match this Sunday as part of the selection process.
The game, between the Probables and the Possibles, is being staged at Melksham RUFC on 9 September, with a 2.30pm start.
Melskham will also host the West of England v South West fixture.
Meanwhile a Regional Carnival, also involving East of England and London & South East, has been arranged for Sunday 23 September, at a venue to be confirmed.
West of England Manager Chris Chatten said: “The squad is made up of players from clubs across a large geographic area spanning such as Reading, Southampton, Portsmouth, Swindon, Oxford, Somerset, Bath, Gloucester and Cheltenham.
“Many new players have been selected for the programme this year, which is pleasing to see, and standards are also improving on the field.”
Sunday’s sides are:
PROBABLES: Luke Schofield (Reading), Rory Penfold (Portsmouth), Jordan Hunter (Portsmouth), Rob Sully (Bath), Rees Gogg (Oxford), Lawrence Haywood (Bath), Connor Breen (Bath), Kerry O’Sullivan (Reading), Lewis Chick (Reading), Jonny King (Bath), Kyle Armston (Portsmouth), Joe Collins (Swindon), Wes Dugan (Portsmouth). Subs: Charlie Price (Southampton), Nick Tuckett (Swindon), Ben Thyer (Bath), Sean Sheppard (Portsmouth), Jack Monk (Somerset), Steven Grant (Bath), Dan Hinton (Somerset).
POSSIBLES: Josh Verity (Swindon), Alex Heron (Portsmouth), Jack Daynes (Swindon), Rhys Evans (Swindon), Reece Walters (Southampton), John Boucher (Reading), Louie Richards (Oxford), Henry Beer (Swindon), Doug Chirnside (Oxford), Kieran Harvey (Bath), Henners Davies (Cheltenham), Rob Tyreman (Oxford), Todd Johnson (Swindon). Subs: Jake Finley (Reading), Connor Tomley (Swindon), Bradley Walters (Reading), Ben Hosking (Southampton), Henry Gibson (Southampton), Harry Amos (Southampton).