How can we setup Azure AD seperating Intranet AD and Internet AD?

Question

How can we setup Azure AD separating Intranet AD and Internet AD?

I have below azure design.

1. on prem >> site to site >>Landing FW>>application gateway>>vNET
2. Internet >> Application gateway >> internet fw>>vNET

How can i setup AD segmenting users from Internet and users from on prem (Internal)

Any design idea would help. Thank you.