false paths, Synplify

Hello, How does one specify ANY arbitrary path in the design as a false path, using define_false_path in Synplify? define_false_path lets you specify "-to" "-from" in terms of ports or registers, but not combinational instance pins. "-through" only lets you specify an OR-list of instance pins or nets. These restrictions seem to leave a large number of possible false paths (combinational-pin to combinational-pin, for example) unspecifiable to Synplify. Other tools don't seem to have this problem, noteably XST and Quartus II which allow any number of "through" nets on a path to be identified, thus allowing any and all possible paths in a design to be characterized. Am I missing something? Surely the free tools don't outdo Synplify on this one? Best regards,