Murex, I believe i am starting to understand more. Not sure I understand completely the child/children you mention. So if I make a clock using the same canvas size (that I understand), then, what I understand is: Right click on Center and set parent to Clock back, then click the hands and set their parent to the Center. I hope i understood this, don't want to take up too much of your time.
For grouping, may I choose the option Normal, because the other option does change the parent/child relationships.
Thanks for your help. I'll Try to download some clocks to see if I can find one that is done like you explained, it is easier sometimes when you see how it is done.