Combine multiple legs to 2 races & then 1 Regatta. DNF not carrying over.

I'm trying to combine 2 races (being 4 legs) into 1 Regatta. If a boat is DNF their partial "leg" time is being carried over to the subsequent race instead of the DNF carrying over.

We operate a gate to stop competitors for shipping. this means race 1 is the start to the gate. Race 2 is the gate to finish of day 1.
Then Day 2 we do the same again. Add these 2 totals to give the Regatta Total. I will then be dividing them up into 4 seperate divisions
and then 2 other seperate events (Family & Classic Divisions).

I can't seem to find how to attach the blw file to this message.

Thanks in advance.
Linsay Patterson