Sambandha , Abhidheya and  Prayojana are all Vedic terms . It means to establish a relationship ,  act  in the relationship  and perfect the relationship..

Sabdha brahman is another important and crucial Vedic term. It means a  pure sound vibration emanating from a pure heart and mind , that’s  completely connected to Divinity . When , by good fortune  , one comes in touch with such  a person  who is able to produce such pure sound it  enables one to directly begin to understand, enter into ,and perfect a   relationship with Divinity .Without such a connection, one is left on the peripherals , perhaps within the impersonal effulgence of Divinity.

By continued hearing or reading the works of such pure devotees who can emit pure sound ,  and by especially serving them in many respects,  especially hearing and understanding their trancendental words,  a perfect relationship  in pure love develops , and one can beginto understand the trancendental relationship that such a person has with Divinity , and our own relationship begins to fructify . Thus gradually revealing ones original spiritual form and activities , all these truths have been recorded by the direct followers of Sri Caitanya Mahāprabhu , and indeed Mahāprabhu Himself as the perfect teacher , taught by example , hearing the lila pastimes of Krishna from His devotees.

These topics are all discussed in the Srimad Bhagavatam.

Whether  one is in union or separation makes no difference,  which was demonstrated by Sri Caitanya Mahāprabhu , who experienced the simultaneous feeling of union and seperation at the same moment,  the  highest ecstatic emotions of Srimati Radharani .