A loop is possible, but I don't see a need for such a looping script in the first place. With the right data model, Summary fields and a find performed on the portals' data source table could produce what you need with no loop used at all.
But if you set a variable up as a loop counter with Set Variable [$K ; value: $K + 1 ]
You could use Go to Object ["Install : & $K ]
to put the focus in a different portal with each iteration of your loop.