ok wait, im a little confused by your scenario.
how close is this fight? Is it like 5v5 and your team survives with 2-3 people? Did you Ace them? Who did you kill?
Why are you not using this time (the time they are dead) to go ward baron? You should also take scuttle if you can safely.
If they can come back from being dead, go straight to Baron, take it for free and pressure your lanes then you are not winning this game, you merely got lucky with one teamfights.
If your teammates are dying that late after a "won" teamfight, then the mistake is on them for dying. If they died because they are low from the teamfight, then they should have backed off. If they are dying so late after the teamfight that they are not alive to contest Baron, there is your issue right there.