Password expiry for different groups

Hi AB21805, 

I don't know if your users are synced from an On-premises AD but then you can set different password policies at Active directory administrative center

if you have only a cloud tenant, you can enable the ADDS services and use the following config: 
Create and use password policies in Azure AD Domain Services | Microsoft Docs

If you have an on-premises tenant you can use the "Create a custom password policy" step in above blogpost also within your on-prem AD.

You can see some information about Azure AD password policies here.

Self-service password reset policies - Azure Active Directory | Microsoft Docs

Otherwise you have to use the method that Rudy_Ooms_MVP already mentioned. 

Kind regards,

Rene