Hi @summermcgladrigan , in my small experience it would be enough for clients to send you an invitation to your work email.
Then you would just log in with your email, in the klaviyo dashboard on the bottom left (where you can open the settings to be clear) and you will find all the accounts you can switch to.
First you have to get all the client accounts to invite you, then you'll see it, at least that's how I solved it, at least I don't have to log in with client credentials.
I hope it helped
Gabriele M. | Marketing Automation Specialist @ drop.it