There is no immediate way to do this, but you could do the following:
Make a custom report (Reports -> Create New Report) using the query below.
Export the report as CSV.
Adjust the parameters and remove entries using Excell or similar.
Press the Import IP Ranges button underneath the scanning targets table on the Scanning -> Scanning Targets page.
Select the file you just exported & edited.
select Realstart AS [Start IP], Realend AS [End IP], IPLocation AS [Decription], 2 AS [Time-out], 0 AS [No Ping], 0 AS [No Windows], 0 AS [No SSH], 0 AS [Save Ping IP], 0 AS [Scan new Windows only], 22 AS [SSH Port], 5060 AS [SIP Port] from tsysIPLocations WHERE LocationID > 0