Some Important capabilities of Salesforce to Salesforce

• Automatically publish data from the publisher org. 
• Manually consume data into the consumer org
• Publish data from the publisher's Account object to the consumer's Customer__c object
• System administrators can share all records, but most users can only forward records that they (or their subordinates) own.

• You can stop sharing a related record from its parent record. Select the parent record. In the related list of the record you want to stop sharing, click Manage Connections in the Sent Connection Name column. Then, select the connection(s) that you want to stop sharing within the Selected Connections list. Click the Remove arrow to move the connection(s) to the Available Connections list. Click Save.
• To stop sharing a record, view the record and click Stop Sharing in the External Sharing related list. You can only stop sharing records that you or your subordinates own. When you stop sharing the record with a connection, changes to the record in your organization are not reflected on the record in the connection's organization. The shared record is not deleted from the other organization.
• To stop sharing a case comment or attachment, you must make the records private.

For more considerations and capabilities click here: S2S Considerations