Is there a way to average resistors together to get a tighter overall resistance tolerance?
No.
Because the notion of averaging a bunch of resistor values only works if you can be sure that the error in their values is random, and has a zero-mean distribution.
Typically, neither of these is the case.  First, because the resistors have already been selected for their value at the factory.  Second, because there's no guarantee that what's coming out of the factory that day isn't biased in one direction or another.  So you may get a lot of resistors one day that are right on value, the next they may all be \$75\Omega + 0.025\%\$, the day after that they may all be \$75\Omega - 0.025\%\$
You need to either design your circuit to be trimmed, or you need to pay for the super-precise resistors.  (And note -- even .05% is getting absurdly precise, and you're going to start seeing all sorts of confounding effects from thermal and mechanical issues.  Getting down to 0.005% is going to make things all the worse).