I want Ticket needs to be "closed but unresolved" status without assigning an tech. But Ticket needs to be "resolved" status with mandatory tech assign. how to do this

i.e 

status                                          mandatory tech assign

closed but unresolved                                 NO

Resolved                                                   Yes

Closed                                                       Yes

How can I do this?

MDSDP 9.0  9048 

PGSQL

Mohammad Golam Rabbany
Proud Customer of MESDP