In Dongying Dongcheng, the following places are suitable for gathering and eating for 21-31 people. These places all have large tables and are relatively affordable:

1. ** Old Sichuan Restaurant * *: They have large private rooms and large tables, which are very suitable for large-scale gatherings. Their Sichuan food is also quite delicious and the price is reasonable.

2. ** Quanjufu Seafood Restaurant * *: This restaurant has a spacious dining area and a big screen TV, which is very suitable for holding parties. Their seafood and local specialties are very popular.

3. ** Pastoral Pastoral * *: This restaurant focuses on Mongolian and Inner Mongolia cuisine, and also offers various barbecues and shabu shabu shabu shabu. Their private room can accommodate large tables, which is very suitable for group dinners.

4. ** Dafuyuan Restaurant * *: This is a traditional Shandong cuisine restaurant with elegant environment, which is very suitable for parties. Their dishes are rich and the prices are reasonable.

5. ** Haidilao Hotpot * *: Although it may not meet the needs of a big table, Haidilao's dining experience and excellent service are also a good choice for parties.

the per capita consumption of these places is basically between 51-111 yuan, but the details need to be determined according to the type and quantity of food ordered. If you want to have a more specific recommendation, you can tell me your specific needs and I will do my best to help.