Disgraced GOP operative Roger Stone acted as a middleman between a cult-like upstate group and powerful Republicans, including Senate Majority Leader Joseph Bruno, The Post has learned.

Stone was hired by Albany-based executive-training group NXIVM in early 2006, according to sources.

Weeks later, two high-profile NXIVM devotees, Seagram’s heiresses Clare and Sara Bronfman, donated use of their private jet to the state Republican Senate Campaign Committee, records show. The next month, on March 16, the sisters gave $20,000 to the committee.

Stone, who resigned from his Senate gig in August after being accused of making a threatening phone call to Gov. Spitzer’s father, declined comment, as did reps for Bruno.