Private Tours

Anyone know a site where you can connect with others to share the cost of the private tours? You can have up to 10 in the group and we only have 4 (6 on two days). I’ve been considering booking one for January 2020, but it would be great to add a few people to the tour and share the cost! Might not be necessary given the recent update on the crowd levels for January. Thanks touringplans!