Hi. I am not sure that the fact that your VMS/Samba Server uses WINS is relevant. The actual question seems to me "who is the master browser of the domain/workgroup?". I made a number of tests, with Samba/VMS and other versions (Solaris, Linux, ...), and the behaviour is the same : - if you ask the master browser (in your example , it's ISZKAZ), you have the list of all the members of your domain/workgroup - if you ask a member which is not the master browser, you get only this member, and the name of the master browser.
Anyway, I am not sure this is a Samba feature or a bug, but because the behaviour is exactly the same for VMS/Samba and for Unix/Samba, I suggest to move your question into the generic Samba mailing list.