val df = ... // some data frame
df.groupBy("A").agg(
  max("B").where("B").less(10), // there is no such method as `where` :(
  max("C").where("C").less(5)
)

| A | B | C |
|  1| 14|  4|
|  1|  9|  3|
|  2|  5|  6|

|A|max(B)|max(C)|
|1|    9|      4|
|2|    5|   null|