Spray a bundt cake pan with cooking spray and set aside.
First start with the Peach layer, follow instructions on the package as they may differ based on the brand you use. Usually you just have to mix the package mixture with cold water. Once done, pour it into the bundt pan layer and set in the fridge until jelly is set, 20-30min.
In a bowl pour one cup of cold water and add in 4 envelopes of plain gelatin, stir to dissolve. Pour sweetened condensed milk into a medium-sized mixing bowl. Add 2 cups of boiling water and whisk by hand until well combined.
Pour dissolved gelatin mixture into the condensed milk mixture, and whisk util combined. If the mixture is too warm now, leave it on the counter to cool a little, but make sure it doesn't settle. When the mixture cooled a bit, pour it on top of the peach layer. Place in the fridge for 40 minutes, until the creamy milk layer is set. Once its set, start on the Raspberry layer.
Raspberry Layer: follow the instructions on the package as they may differ based on the brand you use. Usually you just have to mix the package mixture with cold water. Pour it on top of the creamy milk layer and set in the fridge until jelly is set, 20-30min.
To remove cake from the pan, place the cake into a bowl of hot water for a few seconds, cover with the desired serving dish and turn upside down. Place again in the fridge for one hour before serving.
If you use a silicone mold you can skip the hot water step as the cake will be very easy to remove.