Yes, Delivra's Salesforce integration (v2.1) can be used across accounts.
It is important to note that only one account can be setup to send mail through the Salesforce integration; all other accounts can connect to pass data only.
When multiple accounts need to be connected to one Salesforce instance the installation must be performed FIRST in the account that will be used to send mail. This also means that only the account that sends mail with have Salesforce templates to use for mailings.
If an account is connected in error, there is no way to switch the mail sending capability without Delivra's development team intervening. In this situation, a ticket will be created for our Development team and after their part is complete, you will have to re-connect all accounts, starting with the one to be used to send mail. (This is a billable event.)