Yes, it is possible. The idea would be to import the timestamp and type of epoch as a marker with the option Add events from file. You will need to save your Matlab variable as a file, e.g., a .csv file. The marker can be either simple (indicating only the start of the epoch) or extended (indicating the start and duration of the epoch).
Check this post:
How to add new events to Brainstorm - #2 by Raymundo.Cassani
Also, more info on events in Brainstorm can be found here:
https://neuroimage.usc.edu/brainstorm/Tutorials/EventMarkers