C-ISAM reestablish position

I'm using the C-ISAM library and have been unable to determine a method of saving and restoring the current positioning within a file. I want to traverse a file by key, but be able to "reposition" at a known point in the file where the program had previously read - and resume traversal (by key) at that point. I know I can save isrecnum and read a record directly by record number but there does not appear to be a way to set the positioning in the file back to a given record number or address so that subsequent keyed access would proceed from that point. The file may have (many) duplicate keys, so repositioning by doing a key lookup is not a good solution for me. Has anyone encountered (& resolved) a similar need? Roy Hasselman Compusense, Inc.