Hello! It is advisable to check the group rules and regulations first before posting any QR codes from Facebook pages. Some groups may have strict policies against advertising or promoting other pages or groups. If there are no rules against posting QR codes from Facebook pages, it is always a good idea to provide a brief explanation of what the code leads to or what it offers to avoid any confusion or suspicion from other members. It is also important to make sure that the QR code is safe and not linked to any malicious sites or scams.