Replying...
Intro. 6/A branch is in a house, 6/B branch is in a separate house, 6/C branch is in a separate house, 6D branch is in a separate house and each house is adjacent to each other, everyone in these branches stays in the same house, so 6/A students are in one house, 6/B students are in one house.

6/A, 6/B, 6/C, 6/D

@Asion