Get Fetch used for window opner in PopUp.

Hello guys!
I created a button used ribbon workbench. This event button will open a PopUp. My problem is... After I click in this button, on Onload page(popup) I need to get a Fetch used by my window "opner". Its possible?

For example: I opened my active contacts and show my grid with contatcts. In this page there is my button(Open PopUp), when I click in this button I need open my PopUp and in the event of opening the page I need to get the Fetch used for show the list of active contacts. 

Its possible??? Whe have some window.opner.Xrm.Page.XPTOGetFetchUsedForWindowOpner????

Thanks.