Discrete mathematics is a wide field of knowledge. You could start by narrowing as much as possible what the topics of interest are. Ask the teachers, tell them your situation. Teachers are also human...
Then you could decide what's more important: keep working full time, or take a few holidays to study. In my opinion, one learns better without (time) pressure, having time from morning to evening to really enter the topics, deeply. $4 \times 2$ hours is not the same as a straight $8$ hours.
You say "we", meaning probably that you are a group of people facing the same situation (minus the full time job, maybe). What do the others? Could you study with them? Even if you keep working, in the 2 hours evening you could benefit from their studying experience.