Optional Extra with Quantity Management?

[gorkn]

This is a bit of a strange request. I'm fairly new to Prestashop so please excuse the naivety.

I have several products that can be purchased with an optional extra.

• For example, there are 3 x product A and 3 x product B in stock. Product A can be purchased without product B, but product B can't be purchased unless bought with A.
• For example, user 1 wants to purchase product A by itself. The cost of this would be £10.
• User 2 wants to purchase product A and product B together - cost would be £15.
• There should be now 1 x product A in stock and 2 x product B in stock after these orders.

What's the best way to implement this in Prestashop?

I've attempted to add this as an attribute but it seems to make stock management quite difficult as each attribute has its own quantity when these kind of need to be combined.

Any help would be appreciated.

Thanks!

Edited March 4, 2018 by gorkn (see edit history)