there is one account with 2 apps inside

app1 - orders from clients, app2 - contacts who make work on sold order

in app2: each contact entry has  1)  id like "eurorem6701"    2) email id   3) sms id

in app1:   each order entry has same fields (that fields need to be filled in time of assigning order to contact)

assigning order to contact is via selecting contacts's id in dropdown list (in app1)

how can i tune app1 & app2 together so that:

• dropdown list in app1 take list of contact's id from app2
• when i select contact fields email id & sms id in app1 auto-fill same info from app2