Specific price tax included

[Rafayel]

Hi,

I am new to prestashop. I want to set specific prices for a customer group in the catalog. I always set prices with tax included, but when I try to set a specific price for a product, I need to manually calculate the tax excluded price. Then the system calculates the tax included price. Is there a way to write the price included? Now I have to manually calculate the price excluded for all items. Attached is a screenshot.

Here is my business model: 

I have B2C customers and B2B customers. Each have their own price:

For example: 

An item for B2C is 10 Euro (tax excluded) and 12 euro (Tax included)

Same item for B2B is 8 Euro (tax excluded) and 9.6 euro (tax included)

Some of the items are on Sale now and I make 25% discount from the base price of each:

B2C: 12 - 25%=9 (tax included)

B2B: 9.6-25%=7.2 (tax included)

In the best case scenario, I would like the customer to see the following:

B2C: 12 euro scratched out and 9 euro next to it

B2B: 12 euro scratched out, 9.6 euro scratched out, 7.2 euro visible as final price.

If its not possible from Prestashop default options, are there any add-ons to do that?