Lanarkshire beat the record 13-time winners in the final at Dalmahoy in 2016 a year ago before North East did likewise at Newmachar last year.
Lothians are being led into battle in the GolfKings-sponsored event at Cawder on this occasion by newly-crowned South East District Open champion Rory Smith (Dalmahoy).
Joining forces with him in an event starting on Friday are Stuart McLaren (Bruntsfield Links), Stuart Blair (Royal Musselburgh), Sean Marc (Broomieknowe), Michael Bacigalupo (Longniddry) and Kenny Glen (Craigielaw).
“This year’s team was selected from both the LGA and Scottish Golf Order of Merits,” said Reilly. “It’s new team but very strong side and hopefully this year we can go one better.”