Replacing values adjecent to Null values

I have a carbon-c-relay running that aggregates the same metrics from different services into one. This works pretty well, except when one of the services misses a timeframe and a metric goes to 50% because of it.
This isn’t too bad, but when using perSecond() on the graph, it’ll have a null value when it goes down and spike up really hard when it comes back the next timeframe.

My question then, is:
Is there a way to have the value after a null value in a graph be replaced with null as well? So I can just ignore the huge spikes and have a readable graph.