Adding users to a group based on custom attributes

Team,

Have an intresting script i am trying to develop and need guidance. I am trying to automate distribution group membership using custom attributes. Currently i am able to add users to a group based on a custom attribute i set example below:

#Get-QADUser -Enabled -SearchAttributes @{extensionattribute5 = 905} | Add-QADGroupMember -Identity "Sales - Districttest"

Before the above script is run i am removing all the membership of the group as the custom attribute number will change for users if they are transfered, disabled, etc... see below snippet:

#Get-QADGroup -SearchAttributes @{extensionattribute5 = 905} | Set-QADGroup -Member $null

So now i need to do this on a larger scale and i am going to do this using a csv file. Note also the extension data attibute number is also set to the distribution group.

I want to be able to add users to the group where that group extension data attribute = the user extension data attribute.