Yes, you want to create a
~/.ssh/config file. That lets you define a shortcut name for a host, the username you want to connect as, and which key to use. Here's part of mine, with hostnames obfuscated:
With this I can say,
ssh tabs and get connected to host tabs.com as user
me, with key
new_rsa, as though I'd used
ssh firstname.lastname@example.org -i ~/.ssh/new_rsa.