How do I center one object relative to a folder full of objects?

[DW-FP]

I have two folders. They each contain a half-circle that visually combine to make a full circle. 

I have another square shape that is outside of those two folders. I would like to center this square shape to the "circle" made up of the two aforementioned folder. So visually the result should be a square perfectly centered to the (visual) shape of the circle. 

If I were using Photoshop, I would put both folders containing each half-circle into a parent folder. Then Photoshop treats those individual pieces a whole for purposes of alignment and centering. Illustrator seems not to do this unless there's some toggle or something I need to apply. 

Thanks in advance for any assistance. 

[michelew83603738]

I suggest you group the two half circles and then you can center the square with them as if they were one.

[DW-FP]

Thanks for the reply; your recommendation unfortunately does not achieve a different result than what I've already tried. 

[michelew83603738]

Are you changing the paramater for alignment from page to selected objects? Perhaps post an image of what you are trying to do including your layers panel, maybe I am misunderstanding.

[DW-FP]

I'm not sure what you mean with "changing the paramater for alignment from page to selected objects". ...?

Attached are example images that show what I mean when the circle halves become overlapped when centering relative to the square. 

[pixxxelschubser]

You have not grouped the circle pieces as suggested.

[DW-FP]

Correct, I reliaze my mistake now. See my comment on the post marked Correct Answer. 

[michelew83603738 · Accepted solution]

Maybe this helps:

https://youtu.be/E7WQlm5JpNw

[DW-FP]

Yes, thank you. Believe it or not I'm not a novice user but this is the first time I've seen "group" differentiated from simply putting multiple objects in a single "layer". This is tremendously helpful and I apprecaite the time you took to demonstrate it. 

[michelew83603738]

Glad that you got it to work. Yes, a layer does not work like a group and now that you understand that, a lot of things will work better for you. Happy Holidays!