Azure Monitor multiple subscriptions

PMorgan_1116 Do you have multiple subscriptions under a single Azure AD tenant, or multiple subscriptions under multiple Azure AD tenants? If you have everything under a single tenant, you can scope to each subscription from your Azure AD tenant. If you have multiple Azure AD tenants, like an MSP would have, you can use Azure Lighthouse to see all subscriptions under your main tenant (you don't have to be an MSP to use Lighthouse, anyone with separate tenants can use it).

Also, you set up Azure monitor alerts in each subscription, and you set up a webhook as the action in the action group. The action can go to a webhook created on a runbook in an automation account in your central Azure tenant. Azure Monitor sends data in the payload, where you can extract the data of the alert. Then after you've extracted the relevant data, you can do whatever you want through PowerShell. You can have it send a Teams message, or if you have  a subscription with another SMS API messaging service you can send the extracted data over there.