How to join two objects so that one conforms to the shape the other? I am modeling a bottle of 2 parts that need to be joined, however the bottom of the cylinder neck needs to conform to the shape of the bottle's body section. Is there a command that allows wrap these polygons to the polygons of another object's polygons? See below image and you'll see what I am trying to do. Or any suggestions as to the best method to wrap it accordingly?
One way you could get the top to fit to the bottle is with the Shrinkwrap modifier. Here are the steps.

Start by adding a shrinkwrap modifier to the bottle neck. However, that will crush the entire neck on to the bottle, to get around that problem use a vertex group.


Select the bottom edge loop on the bottle neck and assign a new vertex group to it with a weight of one.


Now use that vertex group in the shrinkwrap modifier (pictured above), and you will get the bottom of the neck to match the bottle.