RFC Destination questions

Hello Everybody! Some simple questions about RFC, please help me:

1) Should I have configured <b>only one</b> RFC Destination (type TCP/IP) from ECC to XI, that all ABAP programms would use on a CALL FUNCTION statement?

2) Could I have configured only one RFC Sender Channel as well as only one RFC Receiver Channel for all the interfaces? If that is the case, what about the parameter "Initial Connections" ? If it's value is "1", I can't do two RFC calls at the same time, can I?

Thanks

Julio