Basically you can add any kind of functionality by developing an Ossn component. (see https://www.opensource-socialnetwork.org/wiki/view/737/how-to-write-a-simple-component-for-ossn)

So the general steps here would be:
1. Spending some thoughts on a smart algorithm which people to suggest
2. creating the necessary database requests to reflect your algorithm
3. display the result

Since Ossn in opposite to other communities doesn't do any kind of user tracking (who clicked whom and what how often), step 1 already will get tricky, as there's not much left you can depend on. The thinkable cheapest way would be: Suggest all members who are currently not my friend. Next could be that a friend of a friend of yours could be a friend of you, too. Or someone who liked a lot of your postings.
The rules are made by you, they can be arbitrary complicate ...