Can I highlight/select shared gene targets among several miRNAs or shared miRNAs among several genes?

Yes. First select the miRNAs/genes of interest using the checkboxes in the Node Explorer table on the left panel; Locate the “Highlight shared/all interactions” function on the table tool bar; Choose “Shared” instead of the default “All” option; Click “Submit” button. The shared nodes, the source nodes as well as their connections will be highlighted on the network. You can then perform enrichment analysis on these shared genes. A screenshot is shown below