I'm still pondering over which zigbee version i should use, because it depends on what is possible for my what i want to make.
But i might as well better explain what i intend to make. 
I'd like to be able to let the master node send a 'program' to the endnodes(which will have arduino's btw, i was asking
about standalone zigbee's for prototyping). this program comes from the app on the mobile phone, and should tell
the individual nodes what they have to do. This program (on the endnode) will check one or some input pins, turn a LED on, and,
after x amount of milliseconds (which is also in the program sent), should send a signal to another endnode to trigger that
program (but it could also talk to the master node, which in turn sends a signal to the destination endnode)
I've included a picture to make this more clear:
(edit): dang, the upper left rounded rectangle should represent a mobile phone
(edit2): 'endnotes' = endnotes. osx paintbrush has spelling control? damn. that sucks.
I'm not sure which xbee's i should use, it's kind of a complicated thing i'm trying to get straight hope you understand,
hence all the questions.