Trouble is with alot of these youtube clips is that there just a snap shot in time, people see them and then Base there stocking off them and forget that the clip only shows the tank working well for the duration of the video.
I have a male Rtm in a 150 gallon ....I have only kept him thus far with a female Rtm and a pleco....just with the pleco at this time as I have separated them due to them fighting excessively..I think the advice given so far is correct.,...typically you see people keeping Rtm as pairs in tanks in the size range of mine....however apparently in tanks larger( in that 200 plus range) I would think it MAY be possible to establish a setting with other aggressive or large cichlids,that the rtm might not challenge and with enough to disperse aggression..... seem like I run across you tube videos with people that have large tanks with a bunch of cichlids and an Rtm mixed in there(video not mine)......for sure it would take trail and error and money and probably some fatalities to achieve .....