at a Vesak today at a temple with mixed lineages,. We had to wait to eat until the monks finished. Is this the norm in Buddhist cultures?

I felt this was unfair and somewhat misleading, too, because there were many very elderly laypeople, plus some of the Bhikkhus might not be part of the Aryan (enlightened) Sangha and some of the Lay people might be part of the Enlightened Sangha. I believe it is proper to serve monks first, but at another mixed lineage temple in Oxnard, we never waited, but the Bhikkhus sat first and took food first, but we all sat down and ate together. Are there strict Vinaya rules for this laid down by the Buddha? Thank you for any and all perspectives on this.