There are six teams, including Munster and Leinster, in contention for best runner-up places ahead of the final weekend of Heineken Cup action.
Only Montpellier, with 18 points, can reach more than 20 points.
Munster and Leinster both have 15 points and are the only two of the six capable of reaching 20.*
So if Munster and Leinster both secure bonus points next week and Montpellier win, it will come down to tries scored between Munster and Leinster. Munster currently have 9 and play Racing Metro at home.
Leinster have 8 and play Exeter away.
But if bonus points are not secured by the Irish pair, Northampton, Biarritz and Toulouse come into the equation as they can all potentially reach 19 points without topping their pool.
Montpellier would also end up on 19 if they lost to Toulon but got a losing bonus point.
If they do all end up level on 19, Montpellier, Biarritz and Toulouse would both beat the Irish provinces on try count.
But if Montpellier fail to get that losing bonus point, Biarritz lose to Harlequins away, Toulouse beat Leicester away, and Northampton fail to get a bonus point win away against Glasgow, no team aside from the Irish two could reach 19.
Therefore, bonus-point wins may not be needed.
There will be full live coverage of Exeter v Leinster on Saturday Sport on RTÉ Radio 1 on Saturday 19 January from 2pm.
* As commenter osheaf01 points out: "Toulouse can gain 2 losing Bonus Points away to Leicester, if they score 4 tries and lose by less than 7 points. In such a scenario, they would finish on 20 points and, if Montpellier have also won, eliminate both Munster and Leinster.
They also have the advantage of playing last, so that they will know exactly what is required."