Hello there Anewstart2021,
We understand that you're asking if you can select which device of your friend that you can track, and we'd be glad to provide information on this.
With Find My, only the owner can select which device they're sharing their location from. This is to allow the account owner to have control of their location as allowing anyone else to track a device of their choosing would be a privacy concern. For additional information on this, take a look at the following resource:
Find friends and share your location with Find My
We hope this is able to clear up your question.
Have a great day!