The Ledger "Stellar account viewer" (https://support.ledger.com/hc/en-us/articles/115003797194) apparently one hooks up to just one Ledger account. But I want to have two XLM accounts via Ledger. Can I do that, and if so how?
Use default account and use a different derivation path on login. 44' stands for bip44 standard, 148' stands for stellar and the third number is the account number (0' is the default account). So simply use 44'/148'/1' for your second, 44'/148'/2' third ... account.