Within your Contacts, you can choose to view all Accounts; this will show all of the organizations with which the folks in your Contacts list are associated.

Click as shown below to see everyone who has an Edelweiss account connected with a particular organization.

Within the resulting list, select the “+” icon to add a user to your contacts!

The Show in Account List option you’ll see at the top of the above window will add or remove this particular organization to/from your list of visible Accounts. By default, accounts are ‘shown’.

Note that when sharing a markup, you can either share with an individual contact or with an entire account/organization. When you share with an entire account and send a markup notification email, the email will only go to the individual users included in your Contacts list, but your markup notes will be visible to everyone within the account.