Mishnah Parah 7:1: Five [people] who filled five barrels in order to perform five sanctification [i.e. five sets of ashes], and they instead decided to perform one sanctification; or if [they filled the barrels] to perform one sanctification and they decided to perform five sanctifications, they are all valid. An individual who fills five barrels in order to perform five sanctificaitons, and he then decides to perform one sanctification, only the last one is valid; if to perform one sanctification and he decides to perform five sanctifications, only the first one he sanctified is valid. If he said to someone, "Sanctify these for yourself," only the first is valid. [If he said,] "Sanctify these for me," they are all valid.

חֲמִשָּׁה שֶׁמִּלְאוּ חֲמִשָּׁה חָבִיּוֹת לְקַדְּשָׁן חֲמִשָּׁה קִדּוּשִׁין, וְנִמְלְכוּ לְקַדְּשָׁן קִדּוּשׁ אֶחָד, אוֹ לְקַדְּשָׁן קִדּוּשׁ אֶחָד וְנִמְלְכוּ לְקַדְּשָׁן חֲמִשָּׁה קִדּוּשִׁין, הֲרֵי כֻלָּן כְּשֵׁרִים. יָחִיד שֶׁמִּלֵּא חָמֵשׁ חָבִיּוֹת לְקַדְּשָׁן חֲמִשָּׁה קִדּוּשִׁין, וְנִמְלַךְ לְקַדְּשָׁן קִדּוּשׁ אֶחָד, אֵין כָּשֵׁר אֶלָּא אַחֲרוֹן. לְקַדְּשָׁן קִדּוּשׁ אֶחָד וְנִמְלַךְ לְקַדְּשָׁן חֲמִשָּׁה קִדּוּשִׁין, אֵין כָּשֵׁר אֶלָּא זֶה שֶׁקִּדֵּשׁ רִאשׁוֹן. אָמַר לְאֶחָד, קַדֵּשׁ לְךָ אֶת אֵלּוּ, אֵין כָּשֵׁר אֶלָּא רִאשׁוֹן. קַדֵּשׁ לִי אֶת אֵלּוּ, הֲרֵי כֻלָּם כְּשֵׁרִים:

Mishnah Parah 7:2: One who fills [a vessel with water] with one hand while doing work with one hand, one who fills for himself and for another, or he fills for two at once, both are invalid, for work invalidates the filling, whether for him or for another.

הַמְמַלֵּא בְאַחַת יָדוֹ וְעוֹשֶׂה מְלָאכָה בְאַחַת יָדוֹ, הַמְמַלֵּא לוֹ וּלְאַחֵר, אוֹ שֶׁמִּלֵּא לִשְׁנַיִם כְּאַחַת, שְׁנֵיהֶן פְּסוּלִין, שֶׁהַמְּלָאכָה פוֹסֶלֶת בַּמִּלּוּי, בֵּין לוֹ בֵּין לְאַחֵר: