Is it Possible to add Records to the related list using a custom button and a custom functions?

Is it Possible to add Records to the related list using a custom button and a custom functions?

I have "custom module" which has look up with  "potential" module.Can  i add the selected records from custom module to the potential module in the related list of custom module with a click of a custom button?

Can anyone pls help me?

Thanks
Prudhvi