Shopify Expert -- 2

Taxes!!! I created a shop through Shopify for b2c and b2b. I did the whole thing with an extra login. As a b2b customer you log in and see different page and prices. So there are b2c and b2b products. Now the only problem is that b2b customers must have displayed net prices and the gross price only has to be calculated at checkout and with the invoice. B2C should see the price including VAT. With shopify you can only choose whether you want to display all prices with tax or not calculate any at all.
I need someone to fix that. B2B products need to be seen with net prices but still charge vat at the checkout and b2c has to see prices including vat. Solution without any Apps please!