Biped Animation to Regular Custom FBX Skeleton

Is there a way to transfer biped animations onto a regular skeleton that I have made already?

I have animations on Bipeds and I have a custom skeleton as well. I wish to use the Biped for my animations because it is preference. But now I need it retargeted to the custom rig because this custom rig has IK Bones and such, that are not created with Bipeds.