America’s Health Insurance Plans may have lost two prominent members in the past six months, but AHIP is ready to win them back, according to recent remarks by CEO Marilyn Tavenner.

The departure from AHIP of UnitedHealth Group (the largest U.S. health insurer) and Aetna (the third largest) is raising questions about the future of healthcare advocacy in Washington, DC, including whether competing associations may arise.

“AHIP has set forth a strategy and direction it feels best serves a membership profile and need that does not fit UnitedHealth Group and our diversified portfolio,” UnitedHealth said last June. “AHIP has to respond to its needs and interest of many members, which understandably resulted in a more limited and complicated advocacy focus.”

But AHIP believes it can make its case to bring the former members back. Tavenner told Bloomberg Business last week that she’s made it a priority in 2016 to welcome the two companies back into the fold.

“One of our primary goals is to make sure we meet them at their space and have them rejoin AHIP,” Tavenner said. “From my perspective, the door is open and we want them back, and both of them know that.”

One of the challenges that Tavenner and the rest of AHIP’s leadership will face in this mission is the wildly diverging needs of the organization’s members. Some insurers focus mainly on Medicare, while others concentrate on employee health insurance plans, long-term-care coverage, or life insurance. According to Bloomberg, these issues came to a head after the passage of the Affordable Care Act in 2010.

Reportedly, there may be room to change minds at Aetna and UnitedHealth. Aetna CEO Mark Bertolini recently said the company might eventually rejoin AHIP if the conditions were more favorable.

“I’m going to do everything I can to win them back,” Tavenner said in her comments to Bloomberg Business. “Part of that is about strategy, part of that is about input. The board here recognizes that and wants to work with them as well.”

Aetna Chairman and CEO Mark Bertolini says that his company may consider rejoining AHIP. (FORTUNE Global Forum/Flickr)