I would suggest getting somewhat of a "trough" (like what horses drink out of). Just get a long plastic storage container from Walmart or somewhere like that, and put food in it, but spread it out. I'd say it would be best to get all three of them on the same feeding schedule, not only because it is easier overall, but once your baby is born, most of your energy will be going towards him/her. To get them on the same feeding schedule, don't give them anything to eat during the day, so that they're hungry when you do give them food. Put the container down, and get them to eat out of it all at once. This way, they will get more used to having the other two in close proximity when they eat, and will learn to share their food. I would probably give a little more than what they will eat the first few times, just to make sure that everyone gets enough.
If that works, keep doing the same thing for a week or two (every night), or if you feed them twice a day, first thing in the morning and again at night (make sure it's the same time every night). Once they are all on the same schedule, try putting down three bowls, but in the same formation that they're used to. (So if Milko is on the left, Cindy is in the middle, and Biscuit is on the right, make sure they ALWAYS eat in the spot or order). Okay, well try that and see if it works! I recommended it to another family who has 3 food-aggressive dogs. Keep us updated!