Try creating two serial objects and running something similar to the example below (if you are worried about loosing data you will need to perform some sort of header check). If you want to acquire data at the exact same time you will need to run multiple threads and should look at the parallel computing toolbox.
% Connect to serial port and set properties
serial1 = serial('/dev/cu.usbmodem14101', 'BaudRate', 9600);
serial2 = serial('/dev/cu.usbmodem14101', 'BaudRate', 9600);
fopen(serial1);
fopen(serial2);
while 1
% Get 2 bytes of data from each device
data1 = fread(s, 2);
data2 = fread(s, 2);
% Print the data
fprintf("Data1: %d \t Data2: %d\n",data1,data2)
end
% Close connection(s)
fclose(serial1);
delete(serial1)
clear serial1
fclose(serial2);
delete(serial2)
clear serial2
