Fax Switch I Send Fax From 2 Different Machines Connected To Same Phone Line, How Do I Chose Which One Will Receive Faxes?

I send fax from 2 different machines connected to same phone line, how do i chose which one will receive faxes? - fax switch

I have a fax machine down the stairs and 1, two faxes I sent faxes through the machine, but I change what I use the stairs instead of my office is, you can go upstairs.

Please help.

Thanks