Changing ASIO Input on a track

Hi,
I've been away from PTP for a while and decided to upgrade to the 2019 (2) release. (Been climbing the steep hill that is Reaper.)

My soundcard ASIO driver has 4 input pairs and shows up in the Options> Preferences> Audio> Drivers as expected:
Input Ports 0,1 / 2,3 / 4,5 / 6,7
One output port: (0,1)ASIO 15/16

When I double-click an audio track and select PORT, it shows only ASIO(0/1)ASIO15/16 + ASIO15/16 as the choices

What I'm looking for is ASIO routing choices, or where to select the ASIO routing for that port, so I can choose the ASIO INPUT pair 3/4 as the recording input and 15/16 as the output.
TIA

I may have answered my own ??.
To switch track inputs, open Options> Prefs> Audio> Driver
Highlight the ASIO pair you want to record.
That pair is the input pair on the track you're recording.
To record from a different ASIO pair, go back to Driver settings and highlight the pair you want to record. Rinse and repeat as needed.

There is not an option to configure
ASIO 0/1 >> Track 1
ASIO 2/3 >> Track 2

You cannot record multiple tracks from different ASIO inputs simultaneously, correct?

Yes

After searching through the FAQs for Power Track, I did discover that you can Ctrl-click to select, say, 3 of the 4 ASIO inputs.
( see PTP FAQ #21 )

When you record, the signals from the 3 selected ASIO inputs record on 3 consecutive tracks.

For example,
+ Ctrl-click the ASIO pairs 0/1, 4/5, 6/7.
+ On the PT Track window, select Track 4 as the recording track.
- record some noise / MIDI -
+ Track 4, 5, and 6 now show the input recorded from ASIO 0/1, 4/5, 6/7

Multi-track recording!

Another trick; if you set the track type to Mono Audio instead of Stereo, you can get all 8 inputs on separate tracks, instead of in pairs.

I am using a 8 channel line 6 UX8. The input and output channel assignments are done in the ASIO driver setup not in the PT port settings. I access the driver software in PT by going to audio settings/audio preferences. Note this is not the windows audio input/output screens it is separate Driver setup.