How allow only specific mac address to discover and authenticate pppoe on bridge

RouterOS Beginner Basics
1

hello
just as the title
i have rb750gr3 .. my pppoe server on bridge .. so every device on the network can discover pppoe server and can authenticate :frowning:
how can i make pppoe server discovers and authenticate by only specific mac addresses that i wanted??

thanks ..

2

any idea ??