In order to assure security and to mitigate risks, you can enforce security measures, namely not disclosing publicly or through mailing lists the info about meeting, minutes, documents, etc., namely respecting the recommendations from the European Union Agency for Network and Information Security (‘ENISA’) reference document: https://ec.europa.eu/information_society/newsroom/image/document/2018-30/reference_document_security_measures_0040C183-FF20-ECC4-A3D11FA2A80DAAC6_53643.pdf
A system must be developed for regular info sharing, as well as a ‘red alert’ system for hub members to communicate situations that may be of concern.
The hub shall be constituted by all relevant members coming from all kind of participants. However, complementarily to plenary sessions (suggestion: once every three months) it’s reasonable to expect that some smaller working groups start operating for specific targets and objectives.