Yes that is Floreant, but it seems to be in its dying stages, unfortunately.
If you have 5 items and need to move 3 of them to other tickets then you simply select the item and click on it 3 times, lol. So basically you move one item at a time.
In my case I have to split tickets at least 2 times a day. I have a coffee shop/street cafe in the central business district to I can many customers that will meet friends here for lunch of for a sun-downer after work. In most cases the bill will usually start out as one until one of them leave or by the second or third round one of the others will offer to pay for some of the drinks.
It also happens that the group of people will start out at one table and then later split up ans sit with someone else, for example someone will come in an while he is waiting for his girlfriend he well sit and have a drink with friends, so when girlfriend arrives he will either move or the friends have paid and left.
I am sure that the current "moving" and partially paying option will work, but the way Floreant did it was really easy to split the tickets and still carry on adding orders to the split tickets.
GK