Splits a list of integers into multiple sublists based on certain values acting as separators, and returns a list of those sublists. A separator value is not included in any resulting sublist. If no separators are found, returns the entire list as a single sublist.

Examples:

Input: numbers = [1, 2, -99, 3, 4, -99, 5], separator = -99
Output: [[1, 2], [3, 4], [5]]
Explanation: The value -99 acts as a separator, splitting the input into three sublists

Input: numbers = [5, 0, 7, 0, 2, 0, 0, 9], separator = 0
Output: [[5], [7], [2], [], [9]]
Explanation: Each 0 splits the list, consecutive zeros create an empty sublist

Input: numbers = [1, 2, 3, 4], separator = 99
Output: [[1, 2, 3, 4]]
Explanation: No separators found, return entire list as single sublist