I am trying to create a dropdown list on cards that list different businesses information like departments. How would I be able to reference that list, so that when I add a card in a different area of the DOC and select that company, the only values that I will see in the dropdown are the values that are listed on that businesses card?
If I understood what you are looking for correctly, it is a two step process - you need to link the information with each relevant company. Then in the card, you need to filter using those relationships.
The way that I implement that idea, is to have a table that shows the relationships, in the picture what is shown in the dropdown for Tag 2, is dependent on what has been entered in the column Tag 1. And how determines that, is shown in the second screenshot of the table for Tag 2 entries related to Tag 1.
So what the filter formula says in English is, take the value in Tag (RTR) 1 in ThisTable, go to the table that relates Tag 1 with Tag 2, and display all entries of Tag 2. (All Modules, Acc Payable etc). It will NOT show Subcontracting, because it is linked to PTP.