As has been referenced elsewhere, yes. If you put someone in a room with other people, all of whom are insisting that a certain event happened, he'll start to convince himself it actually did, creating "memories" of the event.
Now, is this "will"? I'd say yes. Our will to be one of the crowd and not stand out is what does it.
I think you might confuse people with your use of the word 'will'. People will assume you mean
free will. I think
'compulsion' would be more accurate. The subjects do not perform an analysis and make a well thought out decision to create a false memory for themselves. They are reacting to a compulsion to fit in, and the compulsion is totally subconscious so that they are not aware of having made any kind of decision or of not having experienced the event.