A method and system for interfacing heterogenous computing networks to accomplish a cross-network that spans at least two networks and has a source node and a destination node. A graph structure is traversed to define a transaction path. The graph structure includes transaction nodes within transfer networks and bridges that span networks. Each node in the graph structure exists on a network and has an associated set of attribute variables that specify supported tokens. A bridge path defined by two nodes spanning two logical networks is determined. The source node and the destination node are also connected via one or more out of band network paths which are separate from the bridge path. Disclosed implementations link the speed and convenience of peer-to-peer conversion models with business-to-business trading channels using a ledger-agnostic overlay and computing architecture to enable value transfers and conversion spanning dissimilar digital communication networks.