search bupa programmatically

hi experts,

we have one non-sap system which is going to use CRM's database at the backend but it is going to use its own interface for front end. this creates a need for CRM to provide business partner search service using which that legacy system can pass on the search criteria field values and crm will return the list of business partners retrieved using those field values. can this be achieved?

i believe in CRM this is either achieved using search helps (in GUI) or using search objects (in Web UI). i do not know how to tweak either of the methods in a z-function module which can be released as a web service.

please give me the inputs on how this can be achieved.

thanks,

Sagar.