Hi Stefan - we can definitely assist; we have done what you are looking to do for several clients, without the use of apps. We would recommend, however, doing this as a kit/bundle using dropdowns. Have a look at some of our past work:https://www.eshine.ca/collections/eshine-kits
This eshine.ca approach uses no apps, and actually deducts products from existing inventories (of the single products sold) when a kit is purchased; items cannot be removed from the 'kit' as it is sold as one item :)
Email us at projects@whitewatersolutions.com if interested.
Cheers!
WhiteWater Web