need some wireless intercoms that can transmit far

[Onceler]

I need them to be able to transmit and recive through a very big house. They need to be able to be added to,I would like to start with four. I saw the Chamberlin intercoms but they have a beep every time you talk on them and there is a one second delay in talking(cut off some of the words) if you use it with batteries.
Radio Shack has a three station set for 59$ but it is FM and I doubt it would have the range that I require.
WireFree Extreme Range Portable Intercom looks ok but I don't know if they have the anoying beeps or voice activation that cuts off words.
I did a google search and those were the two that came up. If anyone knows of some alternatives please let me know.
Thanks