Within Operate you can configure account ID's to always follow the same sequence which is a mixture of the first 3 letters of the account name and then numbers depending on the specified length.
Alternatively you can set up site specific account ID's, In order for this to work you first need to disable automatic account ID's, from under Settings > System Settings > Member Settings where you need to untick 'Auto Generate Accounts Id'.
Once you have completed this, you then need to add the following fields to your location page layout, this article explains the process if you are unsure how to do this.
Import File Tag
Next Account Id
Once added, go to Space > Locations and you can populate these fields for each location.
the import file tag is the prefix sequence you want to be used
the next account id is the sequential number you want to use
e.g to get an account ID of ALD100021 you would
add 'ALD' as the import file tag
add '100021' as the next account id
if your custom account IDs are no longer working, you can try the steps in this article to resolve it Custom Operate Account ID's Are No Longer Being Applied