I don't think you could do this in the integration itself, but you could potentially set up a workflow for each team using a "Run for Search" block that finds the link from your Employee to the ADGroups item and links it to the correct team. This is one way to get the "Contains" operator in play for such logic. You'd need one per team that you want to do this with.
There may be better ways to do this, for instance, if you could separate out the list into one item at a time, you could just place them into a single field on the employee and set up triggered rules to do the linking.
I found a solution using a triggered web service script, which works through the memberOf list and, to make things a little trickier, needed to use the integration web service to build the relationship between an Employee and an ADGroup.
That's a method I had not thought of. Would you mind sharing your web service script and setup for others that need to go about similar tasks in the future?