Hi Al,
Thanks for posting, and welcome to the Breww community! This is a good question. I would recommend, for now, creating a new vessel in Breww which has a big enough capacity for the largest batch you are going to produce; this tank is purely theoretical, and you could name it “virtual vessel”, for example. You would use this vessel to transfer the entire batch volume from the Brew kit into and then transfer out of your “virtual vessel” into as many FV tanks as you need. When you transfer a quantity to a new vessel, you can give it a new gyle number, but if you do not select this option, it will transfer with the same Gyle number.
I would also suggest checking out the feature request for Ability to brew into 2 (or more) FV’s, as this might be what you are looking for and is probably worth a vote to.
Let me know if you have any questions at all about this, and I will be happy to help.