Can SAP Portal provide single sign on integration to other email systems

Hi All,

I have requirement like

Can SAP Netweaver portal provide single sign on integration to other email systems like

1. Microsoft Exchange

2. Google Apps

3. Microsoft Live

4. IBM Lotus Notes & Domino

5. Novell Groupwise

6. Zimbra

7. Mirapoint

Is yes, then please provide some proper reference. If not any alternatives to implement this.

Thanks in advance,

Kalam.