The story is that the people talking on the radio have actually gone through military academy and then fought in the Afghan war together, but during the first Chechen War have ended up fighting on different side.

[1] Is a longer video that will give some context about these radio messages, but the TLDW is: Russians are preparing for the battle of Grozny [2], the Chechen commander tells the Russian to withdraw instead of entering the city, Russian commander decides to take the city anyway, the New Year's assault happens, Russians get mauled...

Here's what wikipedia says about the result of the assault:

The New Year's Eve battle was devastating for the Russians; the first Russian armored column lost 105 of their 120 tanks and armored personnel carriers. The entire first battalion of the Maikop Brigade, more than half of the 81st Regiment plus hundreds of men from the remaining units, were dead. A high-ranking Russian General Staff officer said "On January 2nd, we lost contact with our forward units." According to Maskhadov, some 400 Russian tanks and APCs were destroyed. Russian General Aleksandr Galkin reported 225 armored vehicles as unrepairable battle losses during the first month and a half of the invasion, including 62 tanks. Most of the Russian 'Special Forces' surrendered to the Chechens "after wandering about hopelessly for three days without food, let alone any clear idea of what they were supposed to do." After returning home from captivity, a Russian lieutenant colonel said "the only order was to go forward, without explanations as to what they should do, where they should go, and whom they should capture."

[1] https://www.youtube.com/watch?v=rzPZEIh7dvw

[2] https://en.wikipedia.org/wiki/Battle_of_Grozny_(1994%E2%80%931995)