I'm not an attorney, but I think in most states this would work. Type up a document today declaring that you have a lottery club and list the members - everyone you would want to give money to if you won. Then list what percentage each person gets if the club wins. Write down that you have the authority to purchase lottery tickets on behalf of the club. Maybe even get it notarized to legally verify that it was created before the winning numbers have been drawn.
Make sure everyone on your list can legally purchase lottery tickets. No minors, because everyone on the list becomes a player.
If the club is established prior to the purchase of any tickets, then even if you buy the ticket without collecting from the other members, your gift to them should be only equal to the proportional value of the ticket price - if your mother gets 5%, for example, then you have given her a gift of a nickel at the time the ticket is purchased.
Should you end up in possession of a winning ticket, take it and the memo to an attorney who specializes in estates. They know about gift taxes. She should be able to arrange for the distribution to be made in accordance with the document pre-tax. I wouldn't tell her whether the ticket belonged to me or the club until after I got her advice on the topic. I'd just say, "hypothetically, what if I paid for the ticket but I bought it on behalf of the club described in this memo?"
If you change your mind, just shred the memo. Nobody but you and the notary ever knew of its existence, right?