Did Buddha practice group meditation with bhikkhus, bhikkhunis and laymen, just like in today's meditation center? In today's meditation center, practitioners meditate with others in group sitting. After an hour or so of meditation, the practitioners may proceed to seek advices from the teacher on their progress.

Did Buddha practice group meditation with bhikkhus, bhikkhunis and laymen, and then they may seek advice from Buddha? Is there any such event described in the Sutta?
Yes, it seems he did. For example in DN 2:

10. And when King Ajatasattu came near the mango-grove he felt fear and terror, and his hair stood on end. And feeling [50] this fear and the rising of the hairs, the King said to Jīvaka: ‘Friend Jivaka, you are not deceiving me? You are not tricking me? You are not delivering me up to an enemy? How is it that from this great number of twelve hundred and fifty monks not a sneeze, a cough or a shout is to be heard?’
‘Have no fear, Your Majesty, I would not deceive you or trick you or deliver you up to an enemy. Approach, Sire, approach. There are the lights burning in the round pavilion.’
11. So King Ajatasattu, having ridden on his elephant as far as the ground would permit, alighted and continued on foot to the door of the round pavilion. Then he said: ‘Jivaka, where is the Lord?’ ‘That is the Lord, Sire. That is the Lord sitting against the middle column with his order of monks in front of him.’
12. Then King Ajātasattu went up to the Lord and stood to one side, and standing there to one side the King observed how the order of monks continued in silence like a clear lake, and he exclaimed: ‘If only Prince Udāyabhadda were possessed of such calm as this order of monks!’
(Walshe, trans)