This is still not something that is available in Network Sonar AFAIK... I have just found a way to add all unwanted interfaces to the "Ignore list" without selecting every interface. A little kludgy, but it works:
BULK "Add to the Ignore List" Process:
Start from Network Sonar, Scheduled Discovery Results,
Step 1: Select the Nodes that have "xx new Interface(s)" you wish to Ignore
Step 2: Select "Import Nodes" (I know, counter-intuative, but this is the process)
Step 3: Select "Next" (Device Types to Import, should list the Nodes you selected earlier)
Step 4: Select ALL INTERFACES in the "List of Interfaces" box, Select "Next"
Step 5: Select "Next" for Volumes and Applications phases
Step 6: Click on the "IGNORE" button at the bottom of "Import Preview"
(There is now NOTHING left to select).
Step 7: Click "Import" to finish the import process, then Click "Finish"
Step 8: Select the "Discovery Ignore List" tab, the Nodes from above should be at the bottom of the list
(There should be a Selection Box to the left of each Node, and an expansion "+" to the right of the Node)
Step 9: Expand the Interface "+", Select the Check Box on ALL the "Node" boxes, and any Interfaces you wish to pull out of the "Ignore List"
Step 10: Click on the "Remove from Ignore List" button
Step 11: Select "Scheduled Discovery Results" again
Step 12: Locate the Nodes that were removed from the "Ignore List"
(They should have only a few "new interface(s)" now)
Step 13: Select the Node boxes to the left of the Node name, Select "Import Nodes"
Step 14: "Next" (Device type to Import), assure the "List of Interfaces" has ALL of these "Selected", Click "Next", "Next", "Next" (to the "Import Preview" screen)
Step 15: Select "Import", then Select "Finish"
Your Nodes have now "Ignored" all Unwanted interfaces, and Monitoring the remainder.