In Cytoscape, you can select a subset of nodes including all edge types between those nodes by doing the following: use a filter to select nodes by edge type, then select all nodes connected by selected edges (or Ctrl+7). Follow by selecting adjacent edges (Alt+E). This will select a subnetwork determined by the filtered edge type but including the other edges (i.e. if you'd like to determine which nodes are connected by more than one edge of differing types). Don't forget to actually create the new subnetwork using the button on the toolbar.