Problem stepping through nested array

Im having trouble iterating through this nested array.

I cant seem to figure out how to reference the groups[] first value for each row. I'm trying to insert it into the GroupID column. For example the '2125a02a-f28e-11e4-ad33-89d58f4ed955' in the first one below would be the first GroupID

Looks like:

groups[2125a02a-f28e-11e4-ad33-89d58f4ed955]
0	4ec28c6a-6294-5329-fe01-57dc3228e4c2
1	a6a1f81f-33f1-79d8-3f61-5c8fb5e27e16

groups[24cd7e3c-f28e-11e4-ad33-89d58f4ed955]
0	4ec28c6a-6294-5329-fe01-57dc3228e4c2
1	364a7c59-da10-567d-268d-57dc323de111

groups[3efd3a5e-f28e-11e4-ad33-89d58f4ed955]
0	4e666186-4c18-eb53-c36a-5cebf8286305
1	4ec28c6a-6294-5329-fe01-57dc3228e4c2
2	a6a1f81f-33f1-79d8-3f61-5c8fb5e27e16

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I'm iterating through it like:

foreach($groups as $group)
		{
			foreach($group AS $rep)
			{
				DB::table('connect_teams')->insert([
				'dealer_id'	=> $dealer_id,
				'UserId'	=> $rep,
				'GroupId'	=> how to get the $groups[currentvalue]??
				]);
		
			}
		}

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any help would be much appreciated