User exit while creating delivery (VL01N)

Hi Experts,

Is there any User Exit, While creating Outbound Delivery with reference to Sales order using VL01N,subitem cannot be created without the related H.Level item.

So my requirement is:

Check Higher Level Item (VBAP-UEPOS), If Higher Level Item value is set for an item, ensure that the related item that the Higher Level Item value refers to is also on the same delivery. If not, then issue an error that sub item cannot be created without the related HLI item.

How to achieve this, Any user exit ? Help will be appreciated.

Thanks,

Ranjith.