sizes dont upload to corresponding men/women conversions

[VerifiedBoutiqu]

We have an online and brick mortar shoe store that sells men, women & childrens shoes.

The problem: Our Men/Womens shoes are not uploading to the corresponding size conversions For example we have a size 3.5 in youth however that conversion is equivalent to a size 5W (Womens).. 

When customers shop by size, we would like those conversions to populate. The shopofy advisors are telling me to achieve this it may be an app or coding solution however the apps are sizing charts..

Would appreciate help!

The photos show an example of another shopify store that does this correctly.. You can see i'm on the size 7 however it also displays size 8.5W...