pyUserPortals is list property. In order to get use in reporting create declare-index on pyUserPortals property.
Let say Index-pyUserPortals class is created to store indexed instances of pyUserPortals.
Now create report in Data-Admin-Operator-AccessGroup class and join with Index-pyUserPortals class on .pzInsKey of Data-Admin-Operator-AccessGroup equal to pxInsIndexedKey of Index-pyUserPortals . For reference you can refer declare index on pySkill.
You can perform an obj-open of the class: Data-Admin-Operator-AccessGroup and provide the property: pyAccessgroup with the required access-group name. Then get the pyPortalLayout of the pyUserPortals page list and set it to required page list to display the portals.