Creating Connections Between Forms?

I have a database that tracks my client information. The forms also include the agent servicing the client and the referral source from where the client came from. I also have tables and forms for each referral source and agent. Currently, if a client is referred by a referral source I go to the referral source table and make a note of it in a text box. Instead, could I tie the referral source and client table together? If, on the client form, I select that a client "Tom" came from my referral source "john" could it tie the client to the referral and note it on the referral form? My referral box on the client form sources the table of my referrals.