Why would you want them to be pushing into the enemy? The purpose of a phalanx (talking about the pikemen here, not hoplitai) is not to kill and it's not to ram into enemy ranks. It is simply to pin them; to keep them engaged frontally so that you can flank them with your mobile infantry and smash your cavalry to their back.

Just keep all your phalangites as a solid line in the center/front of your army and set them on defensive mode. Then use your missile units to provoke the enemy infantry into attacking. Your phalangites shouldn't need to be given any orders, they should be able to stand their ground on their own. So long as you can overcome your enemy on the flanks with your other units, you should have enough time to set up a double envelopement or hammer & anvil.

Here's a quick ASCII diagram showing a basic formation for a well balanced combined arms army:

Code:
P = phalangites
I = infantry
M = missile
S = skirmishers
C = cavalry

         (enemy)

    S       S      S
I I P P P P P P P P I I
C   M       M      M  C