Just then Maruko had a feeling that the group seemd to be divided into the three people A,B,C, and herself and D and E.
The only meaning I can find for 地割れ is "cracks in the ground". I get the general meaning that Maruko's friends are divided into two groups. But I can't figure out what 地割れができて means. Literally "able to make cracks"?
Also I'm a bit confused because there seems to be no subject for the verb 分ける. The subject is obviously her group of friends, but is it ok just to leave that out of the sentence?