How to Customize Lookup field in a form

Hi ,

I have a requirement to customize lookup field .

what i need for demo when we create any customer or vendor we get a lookup in name field with general and roles . when i click on roles name comes with different roles i have to restrict all the name with a specific role like customer , worker or vendor. and other name with different role can show in lookup .

i am new in ax so please suggest me how to solve this any suggestion is very helpful for me  .

Thanks.