For the greatest control you should look at https://www.mathworks.com/help/dsp/ref/dsp.audiofilereader-system-object.html and https://www.mathworks.com/help/audio/ref/audiodevicewriter-system-object.html and you should consider streaming data from the source instead of using 10 second files.
Otherwise, read the file with audioread() . Create an audioplayer() object https://www.mathworks.com/help/matlab/ref/audioplayer.html . Configure a TimerFcn callback with a TimerPeriod of 7 seconds and configure a StopFcn callback. play() the first object. When the timerFcn callback fires at 7 seconds, audioread() the second file and create a second audioplayer object for it and set up TimerFcn and TimerPeriod and StopFcn for it, and then return from the timer callback. When the first object hits the StopFcn callback, that callback should play() the second audioplayer() object.
This setup does not promise no delay: there will be the delay of firing the StopFcn callback to invoke the play() of the next file each time. If that delay turns out to be too much then you will need to switch to the audiodevicewriter system objects that I linked to before.
