If it would work to just hide the resources from Manager 1, do this:
Create a User Group and put Manager 2 and the admin Super User in it.
Create a Resource group and put Article 2 in it.
Connect the two with a Resource Group Access ACL entry with a context of 'mgr' and a policy of 'resource'.
That will "protect" resource 2 from everyone not in the group.
The other way around:
Put Manager 1 and the admin Super User in a new user group
Put resources 1 and 3 in a resource group
Connect the two like you did above.
---------------------------------------------------------------------------------------------------------------
PLEASE, PLEASE specify the version of MODX you are using . . . PLEASE!
MODx info for everyone:
http://bobsguides.com/MODx.html