Creator and "share with" option interfere with each other

[RM]

Hi, 

while testing my Service Management Project I discovered an edge case (at least I think it is one), for which I couldn't figure out a solution yet and also couldn't find anything in any Discussion. Here is my Problem:

Structure: Test User 1 works for Organization 1.

Test User 2 works for Organization 1 and 2.

Test User 1 creates a Ticket within Organization 1 and shares it with Test User 2. Now the Service Desk Agent unintentionally changes the  Organization to Organization 2, which Test User 1 is not part of. Test User 2 still sees the ticket as he is also part of Organization 2. But as Creator, Test User 1 also sees the ticket, which he shouldn't theoretically be allowed to do (even though he created it), as he is not part of Organization 2.

I know there is the possibility to prohibit changing the Organization with hiding out the organizations field on the edit screen etc. But in my company for special reasons this is not an opportunity, the field needs to stay visible.  

So my question basically are 2:

1) Is there a possibility to prohibit changing the organizations field after the ticket was first created? (which would be my preferred way of doing it, but according to some discussions in this forum this seems not to be an option)

2) Is there a way to prohibit the Creator (Test User 1 in my Scenario) from seeing his own tickets, when he is not part of Organization his ticket got moved into?

As described at the beginning, it may sound like a unlikely scenario, but you never know...

Would appreciate all proposals on how to solve this issue. 

Thx, 

Best Regards,

Robert