9
Deal with the people in your syndicate properly
Office pools are where lottery wins turn into litigation.
If the ticket came from a pool, stop and get the lawyer involved before you claim. Who is in, what each person put in, whether that week's contribution was collected, these become extremely contested questions the moment there is money.
Some lotteries can pay multiple claimants on one ticket if it is set up correctly at claim time. Doing it that way is enormously cleaner than one person claiming and then distributing, which can be treated as a gift from them and taxed accordingly.