I have a website that I need different UI according to audiences who visit my website. For example group A and B. I want different home page, about, authentication system, middleware and... for group A and different home page, about, authentication system, middleware and... for group B but I want them to be under one domain and brand. I just want separate them by subdomains like "example.gpB.com and example.gpA.com" but how can I do that with next js 15 ? any solution ?