I'm working my way into the Zoho One suite of apps and I have a two-part question about the relationships between the various portals and apps in the suite.

1. Relationship between portals:

I've noticed that some of the apps have a portal functionality. However, the portal created in each one seems to be separate from each of the other ones. I can create a portal in Zoho CRM and in Zoho Invoice and in Zoho Subscriptions. They each have a different URL - respectively the URLs are:

https://crm.zoho.eu/portal/mybrand/crm/login.sas

https://invoice.zoho.eu/portal/mybrand

https://subscriptions.zoho.eu/portal/mybrand

2. Relationship between apps:

What is the organizing philosophy of Zoho when it comes to customer information? The fact that a different portal is being created for each app makes me feel that the approach is more fragmented than it should be. CRM stands for Customer Relationship Management and CRM is supposed to be the central repository of customer information. All other functionalities should draw on data from CRM and should sync data back to CRM. I should be able to look up a customer record in CRM and see all of that customers purchases, invoices, subscriptions, etc. Even if subscriptions, for example, are managed in a different app, the integration should be such that all subscription information about a customer is synced back to that customer's central CRM app.

If this approach is followed, then there is no need for a different portal for each app. The Subscriptions app, for example, would not need to create a portal; the customer should be able to log in to the portal that is provided through CRM and see all of her/his information there, including subscriptions-related information.

Is this not the Zoho approach? If not, why not? And if so, why is there more than one portal that a given customer can access?