JSON from a gallery that contains a joined gallery

[ander]

I have a Gallery that contains another Gallery.
I need to make an XML file with all this information, but I can't parse it to JSON.

Gallery (Clothes) contains "N" clothes, and each Clothes contains "M" printed logos.
It looks like is a loop in a loop.

My last try was to put in a label inside the items of the main gallery (clothes) with de JSON code of the joined gallery (logos), and then repeat the process outside in another label with the full JSON code.
Like:
Set(_JSONlogos;JSON(gal_logos_clothes.AllItems;JSONFormat.IgnoreUnsupportedTypes));;
Set(_JSONtextil;JSON(gal_clothes_order.AllItems;JSONFormat.IgnoreUnsupportedTypes & JSONFormat.IgnoreBinaryData))
But it returns a NULL.
Any suggestions?