If you have a valid Bitrix24 On-Premise license, you can enable calls for groups of 12 employees.
Step 1. Install the Telephony module
Go to Settings > System settings > Modules > find the Telephony module and click Install. If the module has already been installed, skip this step.
Step 2. Enable the "Use Voximplant SFU server for video calls" option
Go to Settings > System settings > Module settings > Instant Messenger > enable the Use Voximplant SFU server for video calls option.
Save changes. Now you can use calls for groups of 12 employees.