Ask your dm. Is the only real answer to give you, RAW and RAI, does not say you pick a group, only that if the weapon you choose with that feat, you can then apply that feat to all weapon of the group that they are in. RAW seems to suggest that since bardiche is in both the AXE and POLE group weapons, you get to use said feat on any one of the weapons in those two groups.
This really should not be a problem, because all the weapon feats that can be used for this are fairly low and weak feats, your talking +1 to hit, +2 damage or improved crit-range on limit selection of weapons.
Compared to barbarian raging and getting a bonus on all melee weapons, or a urban barb that use fineness weapon and ranged weapons get a bonus on all of them. which is a much larger grouping.
All this feat really does is saving you from having to retrain a few feats via retrain rules or your bonus feat every 4 levels as fighter, if you happening to find a better weapon. Say a +4 Great axe instead of your +1 bardiche