Combining Probability/Forecasts within Groups

I am familiar with the concept of combining forecasts. In the simplest scenario, that could be just averaging the forecasts. For example, let's say I have three forecasts representing the likelihood of an event such as (35, 50, 40). The combined forecast would be (35+50+40)/3 = 41.67 (although I realize there are some more sophisticated methods). This seems straightforward enough. Although I understand there are some risks associated with this, I was under the impression that combining forecasts is a common approach as in this question's answers.

However, let's say I have a situation that has multiple forecasts for multiple different groups (alternative options). As an intuitive example, a list of orders to be picked up from different locations.

order  prob  location
1      0.4   A
2      0.5   A
3      0.35  A
4      0.95  A
5      0.6   B
6      0.5   B
7      0.75  B
8      0.15  B

Each order has a probability of being accepted (i.e. forecast). I want to say the probability of which location an order will be accepted. My initial instinct was to average the probabilities but I'm hesitant.

Note - the number of probabilities could exceed 100 per group and there could be >20 groups.