OK. To make sure I’ve got the idea I want to ask again. You are not asking for splitting a ticket. You are asking for splitting a single item between tickets. For example 3 customers wanted a bottle of $100 whiskey and you want to split this whiskey to three.
We can create $33 whiskey in each ticket but it won’t work because this will decrease inventory by three. Another solution might be splitting it to 0.33 Whiskey on each ticket but this is something weird 
So first of all we need to find a way to distribute whiskey into tickets…
Another solution might be creating a fourth ticket for shared items. So you’ll print 4 bills. 3 of them are individual bills and the fourth one is the shared bill. We can also print how much each person will pay under this bill.
If you can help me about how it should work maybe we can find a better solution.