Starwood Hotels & Resorts Worldwide is in the pilot stage of a secretive guest loyalty program that targets the most valuable frequent travelers from rival hotel companies and even its own Starwood Preferred Guest program.

The as-yet unnamed program, which was first reported last week by USA Today’s Barbara De Lollis and subsequently confirmed by the company, began late last year with invitations to “thousands” of consumers, Mark Vondrasek, Starwood’s senior vice president of interactive and loyalty marketing, tells De Lollis.

The precise selection process for invitations is confidential and proprietary, but Vondrasek says Starwood is considering factors beyond stay frequency. “For instance, we evaluated factors including guest’s profitability, their lifetime growth potential and their ability to influence travel by others,” he says. “We even targeted some travelers who were loyal not to Starwood, but to our competitors.”

Much about the program remains secret, but Vondrasek says Starwood is trying to create “individually tailored experiences” for these guests, centered around one-on-one relationships with guest service representatives known as Starwood Ambassadors.

Starwood reports market share growth and improved guest satisfactions since launching the pilot program, and the company plans to expand it as a result.

The company is being secretive about the program due to competitive concerns. “We have deliberately kept this initiative ‘under the radar’ and divulged very few details, even internally,” Vondrasek tells De Lollis.