Filtered Selectlist

[serdar geniş]

Hi there;

I have a selectlist for cities. For example;

• Amsterdam
• Budapest
• Athens
• Ankara
• Oslo

user_group_1 responsible for 

• Amsterdam
• Budapest
• Athens

user_group_2 responsible for

• Ankara
• Oslo

user_group_3 responsible for all cities

• Amsterdam
• Budapest
• Athens
• Ankara
• Oslo

I need to show only the options users responsible for.

How can I do that.