This is not too difficult. It will look something like this to get the text between the second and third /:
NumberVar slashAt;
StringVar result := {MyTable.MyField};
//find the first slash
slashAt := InStr(result, "/");
//get the second slash
slashAt := InStr(slashAt + 1, result, "/");
//get the first part of the substring
result := mid(result, slashAt + 1);
//find the third slash
slashAt := InStr(result, "/");
//get the final result
result := left(result, slashAt - 1);
result
You should be able to figure out how to get the other part from here - it will need to be in a separate formula from this one.
-Dell