RC question in combinatie with Xbee

Hello,
I'm new to the Arduino and I have a question. I used to buy a lot of very expensive encoders/decoders form the big rc-companies, with an arduino it should be a lot cheaper and mor flexible. I want to rebuild my model boat with more functions. Therefore I want to use two Arduino's with a Xbee connection. So far so good I thought, but...

I know it is possible to connect a pot to the analog and use them for servo's. But Can I also use all the Input from Unit 1 (transmitter) on Unit 2 (receiver). So if I put a switch on Digital 1 it also switches Output 1 and that for all the I/O ports. So I can use 1 Arduino to control 6 Servo's and 8 switched functions. Or doesn't it work that way? And are the Xbee unique. Because I want to use more then 1 Tx/Rx arduino combi in a boat. There is a lot of info availeble, but I haven't seen a lot for this kind of implementation.

Thanks in advance,

Danny
Netherlands, Europe