Hi @mdlew,
If you want to create multiple “tags”, you can create a custom profile property as an array/list field, which allows for more than one item in the field. Note that a custom proiperty is attached to the profile (email) of the recipient, and not the specific list. Here is info on data types in Klaviyo.
Also, Klaviyo uses the word “tag” in a different way - you create tags to allow you to flag campaigns, lists, segments and flows so you can filter for those items quickly. I’m not aware of a way to import them, unfortunately; I had to create mine manually.
Also, I’m confused about why you need to sort by organization - is that because you only want to send that campaign to specific organizations? If so, then I think the best idea would be to use segments (I know, you said you don’t need them right now). Segments would allow you to filter by the company, and then send the campaign to the specific segments that you require. You can also set up segments for several companies - ie, anyone who has a company name of A, B, and/or C.
Apologies if I’m not understanding what you are trying to do. Good luck!