Mail enabling users based on ou and sec group membership

Hello, E2013CU5 here.

i have several OUs in AD and inside them there are "generic users" which idon't want to mail enable when bulk enabling mailboxes for the first time.

How do i mass enable users filtering by OU AND group membership or some other kind of easily set atttribute?.

To test i already made a security group in the OU "laboral" and added the users

researching hasn't shown a clear way to do this.

I tried different permutations of get-user with filters based on OU and group membership, it comes out empty every time:

[PS] C:\Windows\system32>Get-User -RecipientTypeDetails User -OrganizationalUnit "Laboral" -Filter { MemberOfGroup -eq "
Con correo laboral" }
[PS] C:\Windows\system32>Get-User -OrganizationalUnit "Laboral" -Filter { MemberOfGroup -eq "Con correo laboral" }
[PS] C:\Windows\system32>Get-User -RecipientTypeDetails User -Filter { MemberOfGroup -eq "Con correo laboral" }
[PS] C:\Windows\system32>Get-User -Filter { MemberOfGroup -eq "Con correo laboral" }
[PS] C:\Windows\system32>Get-User -RecipientTypeDetails User -Filter { MemberOfGroup -eq "Con correo laboral" }
[PS] C:\Windows\system32>Get-User -OrganizationalUnit "Laboral" -Filter { MemberOfGroup -eq "Con correo laboral" }

Also tried adding the $ sign to the end of the string, same results.

if i try with -ne "string"$ then it's as if nothing exists because it shows the smae output with or without that statement

I then tried to filter by adding a description text(which is easy to do in ADUC as it's one of the values that can be mass edited) but "description" is not a valid -filter type!, and custom attributes cannot(AFAIK) be mass added by selecting and then right clicking-properties

So how can i do this?