אבן העזר קע״דEven HaEzer 174

Se’if 1א׳

יְבָמָה שֶׁהִיא אֲסוּרָה לַיָּבָם, בְּלָאו אוֹ בַּעֲשֵׂה אוֹ בְּאִסוּר שְׁנִיּוֹת דְּרַבָּנָן, הִיא חוֹלֶצֶת וְלֹא מִתְיַבֶּמֶת, וְצָרָתָהּ אוֹ חוֹלֶצֶת אוֹ מִתְיַבֶּמֶת; וְאֵין חֲלִיצָתָהּ פּוֹטֶרֶת צָרָתָהּ, אֲבָל חֲלִיצַת צָרָתָהּ פּוֹטֶרֶת אוֹתָהּ. וְאִם עָבַר וּבָא עָלֶיהָ, קְנָאָהּ, וְנִפְטֶרֶת צָרָתָהּ. וְאִם רָצָה לְהוֹצִיאָהּ, מוֹצִיאָהּ בְּגֵט:

A yavama (a widow who must perform a levirate marriage with her late husband's brother) who is forbidden to the yavam (her late husband's brother), whether through a negative commandment [in the Torah], or a positive commandment [in the Torah], or is a secondary [relative of his] on a Rabbinic level, she performs chalitza (action by which a yavama is permitted to marry a non-yavam) and does not perform yibum (a levirate marriage), and her co-wife performs either chalitza or yibum. And her performance of chalitza does not exempt her co-wife [from having to do chalitza or yibum], but the chalitza of her co-wife exempts her. And if he violated [this rule] and engaged in sexual relations with her, he [thereby] acquires her [as his wife] and this exempts her co-wife. And if he wishes to divorce her, he divorces her with a get (a divorce document)

Se’if 2ב׳

הָיְתָה אֲסוּרָה לְבַעְלָהּ בְּאִסוּר לָאו אוֹ עֲשֵׂה אוֹ אִסוּר דְּרַבָּנָן, וּמֻתֶּרֶת לְיָבָם, יְכוֹלָה לְהִתְיַבֵּם; חוּץ מִמַּחֲזִיר גְּרוּשָׁתוֹ מִשֶּׁנִּשֵּׂאת, וּמֵת, שֶׁהִיא חוֹלֶצֶת וְלֹא מִתְיַבֶּמֶת, וְצָרָתָהּ אוֹ חוֹלֶצֶת אוֹ מִתְיַבֶּמֶת:

If she was forbidden to her husband by a negative commandment [in the Torah] or a positive [commandment in the Torah] or a Rabbinic prohibition, and permitted to a yavam, she can perform yibum; except [in the case of] a man who brings back his divorced wife once she was married and he dies, she performs chalitzah and not yibum, and her co-wife performs either chalitzah or yibum.

Se’if 3ג׳

אֲחוֹת חֲלוּצָה, אֲסוּרָה מִדְּרַבָּנָן. לְפִיכָךְ, נָפְלָה לִפְנֵי יָבָם, חוֹלֶצֶת וְלֹא מִתְיַבֶּמֶת. וְכֵן צָרָתָהּ אֲסוּרָה מִדְּרַבָּנָן, וְחוֹלֶצֶת וְלֹא מִתְיַבֶּמֶת:

The sisters of a woman that you did halitzah with are forbidden to marry, by rabbinic decree. Therefore, if the sister of the halutza "fell" to the yabam (meaning, she is married to another brother of the yabam and her husband died), they cannot marry and do yibum (since her sister already went through the process). She needs Halitzah to permit her to the world. Her co-wives (other wives of her husband) have the same law, by rabbinic decree.