Implementation of whitelists with three different discount rates to Etherum Smart Contract

I will create a smart contract. The project is on the TestNet. Token is ERC20 Ethereum token. I am testing a crowdsale with discount. Token name is TestXY (TXY) Example Normal price rate 100 TXY = 1 ETH There are 3 different groups on Crowdsale. Group A, Group B, Group C Group A - %15 discount - 1 ETH = 115 TXY Group B - %10 discount - 1 ETH = 110 TXY Group C - %5 discount - 1 ETH = 105 TX Non Group A,B,C investors - 1 ETH = 100 TX Each groups have 100 Ethereum Addresses.