Change main image only for first product of the bundle

Hey there,

In my shop we sell products and services associated with them (for example, clock + monthly subscription to access our APP + monthly SIM card subscription). We’re using WPC Product bundle to configure this kind of variable products with three options:

Colour (variable product)
APP Service (variable subscription/product)
SIM card (variable subscription/product)

If the user changes the colour of the clock then, the image changes and it’s correct!!! however, we want to keep the image of the clock selected although the user changes options on the subscriptions selects. We have left the subscription products without image, but the thumbnail image is changed to the default image of the bundle product every time we choose and select any subscription option.

We only have seen in WPC Product bundle settings that we can desactivate “change image” option for all cases. But we need to keep this option available for the product (the FIRST product of the bundle), not for the rest.

Please, how can we do

Thanks
Cheers