Run multiple charging circuits on the same battery
First, remember you should not be charging it at more than 1C, so if you have a 2 Amp-hour battery, do not charge it at more than 2A. I suspect your charging circuits will not work operating on the same battery, as they will interfere with each other's charge cycle/detection processes.

If you want to charge at a higher charge current (and therefore, quicker charge) and you have a nice big battery (like a 5 amp-hour one for example, single cell) then you may be able to find something like a 3 or 5 Amp charger, often they are dedicated battery charging stations with multiple banks and can do even tens of amps. 

For a small integrated circuit solution, you may find it hard to get much more than 1.5-2A current output. I suggest you do NOT put multiple charge controllers onto the same battery.