Yeah should be possible. I'm going to assume you have a decent comprehension of scripting, but if you're not sure about $ITEMSTATE then check out
this article.
The best way I can think of doing this would be creating individual variables for each item, something like %HAD
ITEM, replacing
ITEM for the actual name. When this variable is equal to 0, this means the character didn't have the item before a POV switch. If 1, it means they did- just like tracking if an event happened previously in a storygame.
Let's say the first item Character A has is bread ($ITEMSTATE1). When you're switching to the next POV, in the link script put something like:
IF $ITEMSTATE1 = 1 THEN
BEGIN
$ITEMSTATE1 := 0
%HADBREAD := 1
END
Then repeat the process for all possible items for the character to pick up. Then, on the next page, the inventory will be clear (unless you want Character B to begin with certain items, in which can you'd add that to the link script too. E.G: $ITEMSTATE7 := 1 $ITEMSTATE8 := 1 $ITEMSTATE10 := 1 to add three items with those reference numbers).
When you're switching back to a character who's inventory you've already "saved", you'd need something like this:
IF %HADBREAD = 1 THEN BEGIN
$ITEMSTATE1 := 1
%HADBREAD := 0
END
Again, repeating for all items. It's just the reverse of what we did before.
If you're planning on two or more characters being able to pick up the same item with the same effects, then you'd need two or more variables for that item so you can use the variable specific to whoever the narrative is being panned to for that item.
A storygame with this basis is something I've also actually considered and may get around to writing and scripting one day, though not with that many characters all with POV changes. 5 sounds like a big challenge, because you're not only juggling 5 different characters, you're juggling exponentially growing diverging storylines. And that's not even considering whether they interact- it will be
a lot easier if these characters don't impact each other's lives, because otherwise you're going to have to have a hell of a lot of tracking variables!
Regardless, good luck with this, sounds like it could be very interesting.