Yes it is possible to have more than one E1 Links on Voice Gateway from Multiple Service Provider.
What you need is PVDM and VWIC Cards with Sufficient ports.
PVDM3 Data Sheet
http://www.cisco.com/c/en/us/products/collateral/interfaces-modules/voice-modules-interface-cards/data_sheet_c78-553971.html
and VWIC3 Sheet
http://www.cisco.com/c/en/us/products/collateral/routers/2800-series-integrated-services-routers-isr/data_sheet_c36-609138.html
Please rate if helpful
Thanks
Haris