In case you didn't get an OGR notification, see my updated post above about the Tortoise scenario.
As for the ACC(essory) port control of track power, I refer you to the following, albeit lengthy and arguably convoluted, thread:
https://ogrforum.ogaugerr.com/...wer-using-aiu?page=1
There have been other threads on this topic. I was trying to figure out how to condense it to the Reader's Digest version but it really depends on exactly what you're trying to do. That is, if you can slog through the above thread without falling asleep or pulling your hair out 
, one of the land-mines you might step on is the so-called DCS watchdog issue, conundrum, rabbit-hole, whatever. Specifically, when turning on DCS command track power to a siding, roundtable spoke, yard spur, etc., you really want any engine on that section to powerup silent and in command-mode shutdown. Unfortunately, the way the TIU operates, this can be a challenge depending on how you wire things up. The above thread meanders its way toward this issue. I think it's kind of instructive to follow the thread to see how the thinking evolves.
Your additional interest/requirement of controlling power to track blocks/sections via either the AIU or a control panel needs additional clarification. For a particular section, what happens if the control panel switch is set to "ON" when the AIU ACC port is set to "OFF"...or vice versa. Or do you want a "master" selector switch which determines that the control panel is active (and ignore AIU ACC ports)...or that the AIU ACC ports are active (and ignore the control panel). Or maybe you want it to behave like a 3-way light switch in your home where either switch can turn the light on/off.
So if you can review some of the issues and drill down to exactly what you're after I think we can set you up in short order. But gazing into my crystal ball, I predict one or more of those $1/relay eBay modules will soon be your friend. 
