Big problem : ( AD Disabled users and user domain list

Hi,

My AD is full of disabled users, because we use exchange 5.5 and other brach office uses exchange 2000 and the ADC created this accounts.

When i'm going to set permirsions for a folder on other server, the user list is very big and slow to show. this is because we have thousands of disabled accounts on the AD.

I cannot delete this accounts.

How i can hide the disabled accounts from the user list, when i try to set permisions for a folder on other server?

Thanks in advance.

Ramon