Administration User Groups

Hello All,

I`m struggling with bugzilla 5.2 administration (on windows). can you 
please help me?

I want to setup groups of users being able to access different products 
(that is works for me), but when such user loads the bug, reassigning is 
not possible, because he sees only himself presented in the list. what 
did i miss in administration?

Also, can i restrict access to particular Components or bugs (I have 
feeling, it was possible on bugzilla 3...)?

And is it possible to restrict access according to the value of custom 
fields?

Thank you very much for answers,

Sincerely yours, Andrei