Looking for an input device for digital coaxial.

Is there something that inputs from at least 2 digital coaxial sources and outputs into the only digital coaxial input in my older surround sound receiver. Something similar to the RF modulator for older TVs and a DVD player.
I am assuming the devices that are for basic RCA connections are not going to cut it.
Thank you,
Yup, MSB has a device that can take up to 6 dig inputs and output from 1 or more. It also works automatically by priority from which source is turned on and the last input fixed or on all the time like for a DSS receiver with a dig out.. It's called a MSB Digital Director and I think I seen one for sale here on A'gon if it's still avail. Will do exactly what you described..plus it's a jitter device helping to reduce the jitter. Go to MSB's web site and ck it out, the Digital Director,,, www.msb.com sounds like it.
If you can manage with just 2 inputs, get a 75ohm antenna switch from RadioShack.