You can get four colours each on the left and right but leave the centre grid clear. Each row would only contain one color, like so:
Pusher characters can then funnel the correct colours into the middle. Other characters have to wait for the blocks to be in the middle, which is a bit more risky. This strategy can fail if the right colors are not coming up to complete the matches in order. Pointman can hold a color that is coming out of order, but it is still tricky to complete.