Choosing a hardhat account when interacting with live network contract

Question

I want to use more than one account when interacting with a smart contract through hardhat. When I run yarn hardhat run <script> I can choose a network as --network <network> when I specify the configurations in hardhat.config.ts, in my case

networks: {
    coston: {
      url: "https://coston-api.flare.network/ext/C/rpc",
      accounts: [process.env.PRIVATE_KEY!],
      chainId:  16
    }
  }

How can I choose which account to use?