Can I select which email account to use when sending out emails using Group?

Unfortunately the SDK does not provide support for this. If you have a number of different email accounts, the one last used/active is perhaps the one picked by the OS automatically. Perhaps OS 3.0 will provide better control for this.

UPDATE: Please read this (courtesy of another Groups User)

I want to assign Bcc/Cc/To etc to individual emails. Is this possible?

Viewed 3146 times since Mon, Mar 9, 2009

I lost all my SMS history and iPhone crashed

Viewed 3895 times since Tue, Dec 21, 2010

How can I make a quick call with Groups?

Viewed 3414 times since Mon, Mar 9, 2009

My text messages don't go out since I upgraded to iOS 5

Viewed 2708 times since Tue, Oct 25, 2011

Groups on iPhone 5 / iOS 6 is not working

Viewed 1243 times since Wed, Oct 17, 2012