Set the GLPI to open ticket for multi-entity groups like it do for multi-entity users.
I'm saying about it:
For use of GLPI multi-entities with technicians having clearances on several entities, it is not necessary to change the current entity to create a new incident in a separate entity. The path to open a new ticket is as follows: the technician begins by selecting the requester and GLPI will determine the entities to which the user has authorization. If it has only one entity, then the creation form is updated and the ticket will be declared in the corresponding entity, but if it has several an additional drop-down list is used to select one on which you want to work.
(Source: http://glpi-project.org/DOC/EN/glpi/hel … icket.html)
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