A shortlist of 10 potential sites in the south of Shrewsbury has been drawn up and a meeting on Monday was told that the eventual location of the hub will be decided behind the scenes.
It would mean six GP surgeries in Shrewsbury being closed and moved to the hub. They are Claremont Bank, Belvidere Medical Practice, South Hermitage, Marden Medical Practice, Marysville and The Beeches.
Gareth Robinson, executive director for delivery and transformation at NHS Shropshire Telford and Wrekin, said: "We are not able to share the 10 sites because of commercial confidentiality."
Mr Robinson told a meeting of Shropshire Council's health and adult social care overview and scrutiny committee that the public and patients have been involved in the process of suggesting sites.
But they won't be asked to help decide on the preferred site location because "they are a matter of fact".
A business case will have to be constructed on what the preferred site location is and Mr Robinson said those are not things that the public can have a choice on.
"It's the most viable option," he said.
A travel impact assessment will be looking into how easy it is for patients to get to all 10 of the shortlisted sites and will form a part of the final decision, the meeting was told. Starting in February the appraisal will take six weeks to complete.
A full site options appraisal report - without public input - will be shared with the extraordinary project board in March for sign-off.
They hope to share a preferred site list to a closed Shropshire Council meeting on March 27. The hub could be built between 2025 and 2026.
Councillor Heather Kidd said: "Surely we should be able to do something on it in public so as little as possible is kept from the public.
"I would hate for the committee to be party to something that looks like a secret process. I hope we can do some in public."
Mr Robinson said he is keen to do this "as transparently as possible".
On the issue of commercial confidentiality he said he would "have to take advice" on what the public can be told.
Land off Oteley Road was previously selected as the preferred site, but a consultation last autumn was postponed so other options could be assessed, including upgrades to current GP surgeries.
Shropshire health bosses believe the hub would represent a significant investment in local GP services, and doctors at some surgeries have said if it does not go ahead, they will struggle to recruit and will face working in buildings their areas have outgrown.