Given the various functions of 的de, it is not unusual to find several 的de in one sentence. In this case, one can omit some of them to make the speech flow more smoothly. Some general rules for this type of omission are:
(i) 的de in a relative clause should not be omitted,
(ii) 的de after a disyllabic adjective should not be omitted,
(iii) 的 indicating possession can be omitted if necessary, and
(iv) when more than one 的 is used to connect a series of nouns, the one that is closest to the beginning of the sentence is generally omitted first.
Wǒ (de ) nà gè piāo liàng de tóng wū shì wǒ (de) nán péng yǒu (de ) dì dì de nǚ péng yǒu 。
That pretty roommate of mine is the girlfriend of my boyfriend’s younger brother.
Xiàn zài zài gēn wáng xiān shēng tiào wǔ de nà gè piāo liàng de nǚ hái shì lǐ lǎo shī (de ) mèi mèi de tóng wū 。
The pretty girl (who is) dancing with Mr Wang is the roommate of Teacher Li’s younger sister.
 Yip, P. C., Rimmington, D., Xiaoming, Z., & Henson, R. (2009). Basic Chinese: a grammar and workbook. Taylor & Francis.