Crediting flights on same itin to multiple *A accounts

I searched but couldn't find an answer anywhere. I will be flying UA TUS-LAX-CLD and would like to credit the TUS-LAX to UA MP and LAX-CLD to TK M&S.

Some questions
1) Is it possible?
2) If not can I credit the whole trip to TK and still get the complimentary upgrade using my UA status?
3) What do I need to do to get it done?

Thanks for your help.

I believe so, but it will require a visit to someone at the airports. Use the UA MP number for the reservation. After landing in LAX, approach the TK desk and ask them to change your BP to your M&S number.

Others with more experience in this regard can illuminate better than I can, but when I flew IST-LAX, I was able to switch my FFP from UA to CO while checking in my bags in IST.

I don't think you can break up the credit. Also without UA number on file, you will not be eligible for upgrade.

I've never tried this, but presumably, if you book using your UA MP number, and at your connection point, switch to your M&S number for your remaining flight, you should be able to do it that way.

Nowadays, I don't think you can credit to one program and get benefits from another. In the past, PMUA had two frequent flyer fields - one representing status, and the other for FF credit. However, going back a couple of years, it became harder to do this, think they got rid of it after a while.

If you leave your UA number on the reservation for the first flight and switch after, in terms of upgrades, I'm guessing any advance upgrades would stick. However, I suspect if any upgrade comes down to a gate list, once you take out your UA number, you will be removed from the list. This is just a guess, though - no presonal expereience.

In the past, I tried to credit the longer flight to CO and swapped out the FF# at IAH President's Club for a short hop (IAH-DFW) to BD (BMI) for 600 minimum miles. The problem is that all the miles for the trip would get posted to the BD account.

I could change the FF# on PMUA reservations at the kiosks inside the terminal and they would get posted to the correct account for each leg.

Anyone else have the same experience?