If memory serves me right, it was Ricardo Rodriquez and Curt Hawkins who replied to Cody, it was Ricardo who brought up that they were all gathered once to watch the Marine 3 I think before a show as an example.
Beside, logic dictates that since they are all hired by the same company, they'll have a corporate email (this has been verified by CM Punk among others), which most talent would check on their phones since they are on the road so much. All Triple H needs to do is send out an email saying when and where to have a meeting and a meeting is set.
The active on the road roster isn't THAT big.
I fail to see how a company the size of and with the resources of the WWE would be unable to stage something as easy as a meeting with part of their staff.