Using SendKeys, sending keys to different workbooks

Salam (Blessings) out there!
I'm using sendkeys function in excel macro to send keys to different workbooks. But only one workbook is getting all the keys. Here is the sample code:

Sub test()
AppActivate "book2 - excel"
SendKeys "abc", True
AppActivate "book1 - excel"
SendKeys "def", True
End Sub

I'm running this code from book1.
As per my knowledge, if everything goes right, than book2 must receive the keys abc, and book1 def. But here excel sending all of the keys i.e. "abcdef" to the book1.
If we remove the line:
AppActivate "book1 - excel"
than excel passes the keys to book2.
What I trying to achieve is that activate a specific workbook or sheet, pass set of keystrokes to it, activate another, pass keystrokes to it and so on.....
I'm pretty much new at excel macros and vba code. So, unable to figure out the problem.
Any help is appreciated.....
Thanks in advance.