While there has been some research on coordination in FLOSS, such research has focused on coordination within a project or within a group. The area of cross-project coordination, where shared goals are tenuous or non-existent, has been under-researched. This paper explores the question of how multiple projects working on a single piece of existing software in the FLOSS environment can coordinate. Using the Ordering Systems lens, we examine this question via a cross-case analysis of four projects performed on the open source game Jagged Alliance 2 (JA2) in the forum Bear's Pit. Our main findings are that: (1) Ongoing cross-project ordering systems are influenced by the materiality of development artifacts. (2) The emergent trajectory of cross-project ordering systems is influenced by affordances that emerge from the interaction between the goals and desires of the project team building the development artifact, and the materiality of the development artifact. (3) When two parties need to coordinate in the ordering system, all or almost all coordination effort can be borne by a single party. Furthermore, over time, emergent FLOSS projects bear more coordination effort than stable, mature projects.