You can add multiple users to your Slash account. To add them:
Visit the entity settings page.
Click on "Send invite" on the top right.
Type in the name and email address of whoever you'd like to invite and assign one of the following roles:
Admin: has full permissions (including notifications)
Accountant: has view only access to transactions
Buyer: can have cards assigned to them and see the card transactions associated with those cards
In terms of notifications, here is what each of the roles will receive:
Admins: get all the same notifications that owners do
Accountant: do not get notifications
Buyer: get notifications on card activity associated with their cards