Arduino Mega Serial to SPI

Hello,

I was wondering if i could use the TX/RX data coming into the arduino mega and send it to the SPI pins on the Arduino? What i am trying to do is have a counter at the serial port and send that information to the spi port. From the spi port i want that information to be displayed onto the BOB4 Video overlay display on the TV. any examples of suggestions will be greatly appreciated !!