Seperate Db instance for certain modules

[kallievz]

Prob a silly question, but what is needed when I want to create a dedicated instance for a certain module.
We do comms, emails and sms's and documents?
So, in short, 3 seperate modules, over 2 db instances. It wont span db tech, all in Sql Server.

Want to have them on a Comms db instance for sms and email - have a single webhook for events from service provider, and no method or setting scope per tenant, we can however send a single parameter with payload to idendify the entry in db, this the single db instance for Comms, and then the documents on their own db instance, but could be on a seperate server with huge storage and minimal hardware eg. file server. All in Sql.

Any idea on how to achieve this? Thanking in Advance.