Hi JP,
Thanks for your request. There is an easy way to connect one input with two or more outputs: Just create one input (with no connected output) and then two outputs connected to the input. You will get a similar result as in the online demo for i-doit pro.
The other way (two inputs connected to one output) is currently not possible with i-doit pro. Can you give us a simple drawing which scenario in real life you would like to document? Maybe there is a workaround.
Greetings
Ben