If your bulkhead fitting is 3" or 4", then I would just put a "T" there and use bushings down to 1" for both hoses running to each tank with a ball valve and filter for each so that you can block them when needed like cleaning the filter when there is a lot of trash there.
I had a 5gpm, 5.gpm and 8 gpm all running off my 325 gallon tank, no problem. I could have done it also with a 200 gallon tank, just have it fed properly. I took one machine off the front of the trailer as it caused me to bend an axle and I did not use it that much.
I would not use more than 1 machine for each 1" hose, too much to risk.
If the bulkhead fitting is only 2", that will work ok, just put a "T" there and on each side of the "T", put a reducer bushing down to 1" and run 1" lines to the machines with a ball valve and filter for each machine. That is how I have mine but I also have another "T" there for filling buckets, washing hands and a 2" dump valve for emptying the tank when I need to.
What Hal meant was buy another bulkhead fitting (most of the vendors have them, Tractor supply, maybe even Northern Tools also) but you have to cut a hole in the tank near the bottom but not too low, put the bulkhead fitting by the bottom and have it a little bit higher so nothing blocks the installation. You will need a holesaw to cut the hole the size of the threaded part of the bulkhead fitting. They are not hard to install, even by yourself, I have done a lot of them over the years by myself.
Let us know if you have any other questions.
