How to parallel run 2 different functions?

Hi, everyone:

Suppose I have two functions called P2 and P3, each function will run N times using for-loop and P2(t=k) requires the results from both P2(t=k-1) and P3(t=k), P3(t=k) just requires result from the previous P3(t=k-1).

I was wondering, is it possible to use the parallel toolbox, so that every time I could run P2(t=k) and P3(t=k+1) simultaneously? (function P3 is very similar to the function P2 but always run slightly slower than P2), because I am currently just run all P3s first, save required results and then run all P2s again.

Thanks