Representatives from Texas health care organizations surround a black box covered in question marks. A box of the unknown is how they describe the health care bill U.S. Republican Senators are crafting to replace the Affordable Care Act.

"It would be helpful to know the details, but the Senate deliberations are happening in a black box," said Patrick Bresette of the Children's Defense Fund of Texas.

Texas Senators John Cornyn (R) and Ted Cruz (R) are two of the 15 Senators writing the legislation.

President Donald Trump met with the GOP lawmakers Tuesday, reportedly telling them the House-approved bill, that he previously praised, is "mean." He called on the Senators to do better.

"I really appreciate what you're doing to come out with a bill that's going to be a phenomenal bill for the people of our country. Generous, kind, with heart. That's what I'm saying. And that may be adding additional money into it," said President Trump.

While the public doesn't know exactly what the lawmakers have in mind, the organization leaders say comments from the Senators imply major cuts to Medicaid are on the table. So 25 organizations crafted a letter to Cornyn and Cruz, asking them to preserve Medicaid and fight for the 1 in 7 Texans who rely on it.

"Over three-million children in Texas rely on Medicaid for their health care. Nearly half of all the births and newborn care in Texas is paid for by Medicaid," said Bresette.

"Medicaid funding supplies in-home services for people with disabilities, like I said, of all ages," added Bob Kafka of ADAPT.

"Medicaid is a lifeline for many Texans with mental health and substance use conditions and the most significant force of mental health funding for people with serious mental illness," said Greg Hansch of NAMI Texas.

And if Medicaid funding is cut, the groups say all Texans will feel it in their bank accounts.

"Local taxpayers, in the end, will have to pick up the costs. Health care does not go away, the need for care does not go away when Medicaid is cut," said Regina Rogoff of the People's Community Clinic.

But Senator Cornyn's office says these fears are based on the House's bill, not what the Senators are working on. Cornyn himself added he's committed to Texans.

"As we get closer to consensus on the best solution, my goal is to continue to make sure Texans have more choices and more affordable coverage and end the mandates and the tax hikes that have caused premiums to skyrocket," Cornyn said.

Senators are expected to take a vote on the bill next month.