Rolling calculation from Total - Zero

I have absolutely no idea if this is possible but I am looking for a formula that does a rolling calculation. I have a total (H1) and I want to subtract the times in column B & C (this is extracted data) away from this and until it reaches zero, or as close to zero without going over, then start the calculation again.

I have attached a sample sheet showing what I am trying to achieve, albeit I have manually entered the results I am looking to achieve. Thanks