Exit/badi for Material group validation on service POs

Hi Gurus,

The requirement is to put validation on 'MATERIAL GROUP' at item level as well as service sub line item level.I have used EXIT_SAPMM06E_017 for line level validation.

For service sub line level 'MATERIAL GROUP' i tried using EXIT_SAPLMLSP_030 but validation is not working properly as

EXIT_SAPLMLSP_030 is triggered before EXIT_SAPMM06E_017.

Kindly suggest any alternatives.

Thanks in advance

Deepika