Influx Database with duration and time - convert to time series

I’ve got influx entries where the record has a time (and end) but also a duration.

I’d like to plot this on a graph where I have a representation for the length of time as calculated from time (start) for duration.

Is there a function where if a record started at 13:00 for 300 seconds, that would create a 1, or other value from 13:00 to 13:05. Or is there some other way I could represent it.
I have a number of hosts where I would like to see if the process (it’s backups) are overlapping. And to do this I need to represent this record as a graph plot to see overlapping.