Anchored items size with javascript

Hi all,

I try to get the size of an item in my InDesign page, with the function geometricBounds.

It causes a problem when my item is anchored to another one : I only get the bounds of the main item and not the anchored one (see the red arrow in the sreenshot).

I can't detect the second item with script, because it isn't a real item, just an anchored item to the other one. I can't make a group with these two items neither.

If I export an image file for this item, I get the main item and the anchored one.

Is there a solution to get the size of the whole object ?

Thanks,