Title says it all, just wondering how this can be done. Any advice?

Try overriding OnBlockHarvested in your block class, then do something along the lines of:
 

 @Override
    public void onBlockHarvested(World worldIn, BlockPos pos, BlockState state, PlayerEntity player) {
        worldIn.setBlockState(pos, Blocks.STONE.getDefaultState());
 		super.onBlockHarvested(worldIn, pos, state, player);
    }

replace stone with the block you want

There is a function in Block that is called onBlockHarvested, you can probably start from there and just replace the block with the other block.

if above doesnt work then switch the super and worldIn#setBlockState, as the super removes the block and then the worldIn#setBlockState places the stone down

https://github.com/Draco18s/ReasonableRealism/blob/1.14.4/src/main/java/com/draco18s/harderores/block/ore/HardOreBlock.java#L115