Okay. (First, I assume you don't
literally mean you want the Output to go to the Input, but are just referring to +Analog Input 1+ & +Analog Output 1+ in shorthand!)
The first thing is to check that your interface supports individual Outputs from Logic (many only support stereo pairs). This should be evident in +Audio MIDI Setup.+ If it only supports pairs, then you will have to pan each Track fully left or right to get separation. However, if it
does support individual Outputs from Logic, then you need to be sure that each channel you are dealing with is a Mono channel, & not Stereo. There is a little symbol which tells you this, near the bottom.
The bottom line is that the options available in the Output selector are the options provided by your interface's driver (software), so if it gives you a choice of:
+Out 1-2+
+Out 3-4+
+Out 5-6+
+Out 7-8+
…etc., then those will be your only options, & you will have to resort to panning. However, if you have an Output object & it allows individual channels to be selected, then you're in luck!