I am new to using bluetooth and am looking for some advice.

I am wamting to setting up a service at an event that we run at church so people can bluetooth photos to a laptop so we can show them via projector, one of my friends used to run this via his Macbook pro, however he has moved away and the USB bluetooth dongle ive got only allows one person to transfer a file at a time, while the Mac allowed simultaneous transfers. At the event having simultaneous transfers is essential really.

If anyone can anyone recommend a solution to my problem that would be great.