Editing this because I misunderstood your question. There are a few extensions/plugins em that will allow you to save all of your tabs and sessions to reopen later. That might be a suitable workaround at least.
The open tabs sync between browser installations when you close chrome altogether. Simply closing a window when another is open is treated the same as closing all the tabs in that window and leaving the others open.
Also the window doesn't really belong to either account. Multiple accounts means both will be logged in simultaneously and share much of the resources.
Looks like I'm wrong about that last part; although my experience seemed to indicate otherwise. But here's what google says about it: