A private group trying to positively influence a protracted water war is edging forward with plans for a possible “transboundary” water management institute. The Apalachicola-Chattahoochee-Flint Stakeholders, meeting mostly in secret this week at Lanier Islands resort in South Hall, voted Wednesday during a public portion to accept a report by an academic group, The University Collaborative, that looks at options for the transboundary group. Members hailed it as a step forward to dealing with water-sharing issues that have long plagued Georgia, Alabama and Florida.