Read data from 2 serial port and forwarding to single port

Hi,

I am trying to write a vi which can read serial data from 2 com ports and write to the single port one by one.

For example:  Read VISA 1 o/p--- > 1 string 

                       Read VISA 2 o/p--- > 1 string

How can i write the 2 strings of serial data one by one @ single port with the help of Write VISA?

Thanks