Run animation with multiple caracters

[moesz59]

Hey, 

I haven't found tutorials for that.

I would like to animate multiple caracters and wondering a way to do it easily.

It's a run so I would like to have more participants.

I've already animate one caracter. For that i drawn it on illustrator then animate it in AE. The second step would be to duplicate this composition and change, for exemple the tshirt color, the leg size.
Is there a way to do that easily by reusing the composition without start from zero for each caracter ?

Thanks for your help

[moesz59]

in order to explain my purpose, here is a short video. 
How can I replace the t-shirt of the second biker (with a spotted one) easily.