import filter when pages in different field

Help.  Am creating a custom filter for a tagged data file.  In the data file the beginning and ending pages are placed in 2 fields tagged SP and EP respectively.  i created a custom filter with both tags listing the Pages field.  When using my custom filter, only the first page imports.

I notice the Web of Science (ISI) filter seems to have a similar logic (using BP and EP) but for that filter both pages end up in the pages field separated by “-”.

Can anyone help me figure out how to import both the first and last page when these appear in 2 different fields?

Could you provide a small sample (1-3 records) of the text file?