Yes the standards bodies require FRAND licensing conditions. And if the companies did not follow strict procedures (including but not limited to FRAND licensin

Yes the standards bodies require FRAND licensing conditions. And if the companies did not follow strict procedures (including but not limited to FRAND licensing) to ensure fairness to companies outside the group they would very much be at risk being an illegal anti-competitive group of companies. In the EU at least the punishment for competition law breaches can be up to 10% of global group turnover. However for the same competition law reasons the standards body cannot fix the price of the patent licenses but must leave it to the individual companies to determine what is FRAND. In some cases a 3rd party licensing agency (e.g. MPEG LA) offers to manage the licensing for many companies and operates in the way you describe but even members of the standards group do not have to join which is OK so long as the prices they charge are FRAND.