I noticed that there are plenty of suggestions here, since it appears that the list of features "looks" pretty simple. This feature list is a bit more complicated than it appears. Read a little deeper........Read it two or three times like I have done. Then the original post doesn't seem so easily resolved.
"The system must use single-line analog sets".
This means that upon going off-hook using a Scooby-Doo phone, CO dial tone is received.
The request is that some digit can be dialed to disconnect the station from the CO line and connect the station to intercom dial tone. Note that the word "digit" is used, not flash key, hold button or speed dial key.
Everybody here has their favorite brand of systems to sell. Upon reading the initial post, it's not to much of a list, so your favorite system will fit the bill. Key phrase: Single Line Telephone. That's where it gets complicated.
I know that this type of thing can be accomplished using a bunch of relays, Viking devices, some 1A2 cards and complicated wiring, but if there is a system out there that REALLY addresses this laundry list, I will be impressed.
