Web Help Desk - Client Companies and Location

Hi for everyone,

I'm new of Thwack community, and I need help...

I'm trying Web Help Desk, and i have this problem:

I've create 3 companies (for example A, B, C), 3 Location associated to companies (Florence with A, Milan with B and Rome with C) and three client (Sam Company A, Tom company B and Paul Company C).

When client connect for create a ticket (via web), the field requested are: Request type, Subject, Request Detail, Location and Room.

Why Tom (Company B) can select in the location menu Florence, Milan and Rome? is possible to limit the choice of the location ONLY to the locations associated with company?

Sorry for english and thanks for help!!!!