Linking framed and non-framed posters together (printful)

[Koenmeij]

Hi all,

I'm currently setting up my products and these include posters. I have added some customization, these include per poster design:
 * Different colour background
 * No frame, A black frame, A white frame.
 * Size of the poster

It seems like I cannot add these options to the products on printful as they would unlink. Therefore they do not show up as additional variants, thus I have to create the following sub-categories:

 * Colour 1 not framed

    * Size selection

 * Colour 1 frame black 

    * Size selection

 * Colour 1 frame white

    * ....

 * Colour 2 not framed

    * ....

 * Colour 2 frame black

    * ....

 * Colour 2 frame white

    * ....

 * ....

 * .... 

I was wondering if anyone knew a clever solution for this, as I do want to keep the products linked, so I'm not fiddling with custom orders all the time. I know there is apps out there for customization, however these either unlink the products OR do it based on the options in the products tab (Since i cannot add options this is not a solution) (See following image:)

Options in shopify that I cannot changeExample of my other product, this works as it is simple.

Thanks for helping me in advance,

Koen