Hey, nice looking model.
If I understand you correctly, when you say you “made them a separate model,” I’m thinking you meant you made each major element of the house a separate group, or possibly component.
Groups and components are container objects. Some number of edges and faces that together form a meaningful unit or structure are placed together inside the container object, where they are isolated and protected.
Even after some number of entities have been enclosed in a container object, you can still edit the container object by entering its context, affording you access to the edges and faces within. Double-click to edit, click on empty space to quit editing.
You can edit the groups forming your house and then select and hide (right-click > Hide) the edges you don’t want to see.