Hi @taylorcluster, from my experience, you typically want to have one domain/platform per Klaviyo account.  You can talk to Klaviyo’s team to consolidate your invoicing/payments into one bill if that’s part of your concern of having multiple Klaviyo accounts. 

There’s a few edge cases where you can have one Klaviyo account for multiple ecommerce platforms (e.g. Regionalized Sites), but almost no scenarios where you want to share different top level domains (TLD) into one Klaviyo Account. 

Especially with the current environment of Google/Yahoo Bulk Sender requirements that require emails to be sent from branded domains that match the FROM: (or Reply-to:) email address.  Sending from Branded Domain A, and representing it as Domain B looks highly suspicious even though your intent is good - I suspect it will soon trigger all sort of internal spam flags or algorithms because that’s what the bad guys do to spam people.  

Also note, you can use one login to switch between the various Klaviyo accounts (between your various brands).  In fact, that’s how we agency partners can access and switch between all the client accounts we work with.

I’m going to link to some prior conversations about this for more context:

Hope this helps!