@Partner Portal & Community (PRM) - We were under the impression that enabling an Account as a Partner and giving them login access to create accounts and opportunities would provide visibility to those "sub accounts" of the Partner account and opportunities to the Account Owner. So if Account "Dealer A" is a partner user, and they create "Dealer A's Customer" and an opportunity, they can see it through the community page, but where is the relationship between the accounts/contacts/opportunities created by the Partner and the Owner of the Partner Account? Thought this was basic functionality.???
@Debra Jensen An older question, and maybe you found a n answer already?
Just as internally, you set up your Sharing model, you need to look at what kind of Sharing model you want for external users as well.
This would be a nice page to browse through, including the links from it:
Prep Your Org for a Partner Community
https://help.salesforce.com/articleView?id=networks_partner_community_prep.htm&type=0