The gas pressure coming out of the quick connection likely is regulated (low pressure). If you still have the regulator on your gas grill, it will probably not work.
The regulator on the grill is expecting high pressure input from the 1lb Coleman style propane can. You'd probably have to tap into the high pressure side of the Airstream tanks or replace the grill's regulator with an adjustable valve.
If you have already removed or bypassed the regulator on the grill, there may be a shutoff somewhere.
2006 Safari SE FB
2000 F150 4.2L
2011 F250 6.2L