[Aruch HaShulchan, Orach Chayyim 372:15][1]:

>בית העומדת בין שתי חצרות, שכל אחת עירבה לעצמה והוא עירב עם שתיהן - יכול לטלטל לכאן ולכאן כל דבר. ואין לומר איך אדם דר בשני מקומות, דאין זה שאלה, דכל אדם יש לו רשות לדור ולאכול בכמה מקומות, וכולם חשובים אצלו דירות.‏
>
>A house which is in between two courtyards, each one having made its own *eruv*, and [the inhabitant of this house] makes an *eruv* with both of them, he may carry anything to both courtyards.
>
>Don't ask, "How can someone live in two places?" This is no question, because every person can live and eat in multiple places, all of which are considered his houses.

I would posit that the same holds true for creating a residence at the time *shabbat* starts in the place where one places one's *eruv techumin*, while simultaneously having another residence (to be used later on during *shabbat*) in the courtyard for the purposes of creating an *eruv chatzerot*.

  [1]: https://www.sefaria.org/Arukh_HaShulchan%2C_Orach_Chaim.372.15?lang=bi