The group "Delegates Unbound" intends to launch a nationwide television commercial this Sunday on potentially multiple cable news outlets.
With less than a month until the GOP's national convention in Cleveland, there are now three factions aiming to open up voting on the convention floor, freeing delegates to vote their conscience for who should become the party's nominee and effectively halting the coronation of Donald Trump.
"We're trying to help bring people together, provide guidance and let the world know this is serious," said Dane Waters, one of the backers of "Delegates Unbound."
Waters said the group will spend between $2.5 million and $3.5 million on the three-day ad buy, calling these next two weeks "telling of whether all the pieces can be pulled together."
The group - a 501(c)(4) organization - is led by Waters, who runs a political consulting firm, and Eric O'Keefe, a conservative strategist, plus A.J. Spiker, a former senior national political adviser to Rand Paul's presidential campaign.
"Delegates Unbound" will begin working in conjunction with Kendal Unruh, the Colorado delegate and convention rules member leading the unbinding charge, and Courageous Conservatives, a super PAC that formerly aided Ted Cruz's presidential ambitions.
The three factions will hold a joint conference call on Friday to discuss coordinating their efforts. The combined group also intends to build a delegate whip operation to counter Trump's planned whip team of 150 paid staffers and volunteers.
"Delegates Unbound" is primarily looking to aid the advocacy efforts of longtime rules member Curly Haugland of North Dakota and consultant Sean Parnell - co-authors of the book "Unbound," which argues, in part, delegates are not constitutionally bound at the convention.
Waters said the organization emailed 1,400 of the national delegates last week with a link to the book but acknowledged the difficulty in contacting delegates because they lacked a complete list of delegate names.
"We are promoting their book because we believe it's the Bible to this issue," Waters said.
Courageous Conservatives, began running radio ads in Iowa on Thursday, encouraging listeners to call RNC rules member Steve Scheffler and tell him to unbind the delegates in Cleveland.
Rick Shaftan, who heads the super PAC, told NBC News on Wednesday the group is "going to be going after a lot of these folks."
"If he says I'm on board, I'll pull those ads instantly — that's what I'm hoping to do," Shaftan said. "They're settled in concrete until the concrete breaks up."
But Scheffler, who is also the state's Republican National Committeeman, is an odd target because he is expected to be a tough sell. He told NBC News two weeks ago: "The people of this country have spoken. Now is the time to get on board and unify, and all these theatrics and doing something silly is not a smart thing to do."
The full list of RNC rules members had yet to be released until Thursday and several involved with the effort to unbind delegates acknowledged the difficulty in contacting potential targets without knowing who they were.
Earlier this week, several rules committee members — who had each backed a candidate other than Trump during the primary — told NBC News they had yet to be contacted by "Free the Delegates" organizing forces.
The conference call on Friday is intended to sync up the movement's strategy and direction.
By Vaughn Hillyard, NBC News