any way to not require acks on loading program?

I am trying to program more than one Arduino board simultaneously, via an XBee module.

It seems that the only thing preventing me from doing this is that the Arduino IDE requires some kind of acknowledgment from the board being updated, in order to load a sketch.

#1 Is that a correct assumption?
#2 Is there a way to prevent this requirement by
A - allowing the Arduino IDE to load a sketch without ANY response from the board(s)?
or
B - using some other method of loading sketches? I don't know anything about this, i.e. using an external programmer, etc.

Any insight would be awesome.
Thanks everyone!

Cheers,
Bill

You would have to rewrite the bootloader for that...

If you look at the source code you'll se that there is a conversation going on between the board and avrdude that arduino uses to upload the programs.

this is the documentation of the protocol. notice that arduino uses version1 of the protocol

massimo