Close your eyes and breathe deeply. Then focus your awareness firstly on your body outline. Then include awareness of your clothes and integrate them into your brain maps consciously. From there, you can play with awareness of your training partners nearby and at different distances. You can start with a single partner but make sure you progress to multiple partners simultaneously. Add a variation by having them at different locations. Then the exercise can progress from closed eyes to open eyes. The initially closed-eye exercises emphasize visualization and reduce the distraction of vision.
Add to it various emotional states from your partners, as well as active and passive focus from your partners on you. You aim first simply to feel the presence and location of your training partners. Then you progress to picking up their attitudes and intentions (make sure you include aggressive and violent intentions). You can also play with movements of varying speeds.
The important aspect is to have a mental concept (visualization) of a field (brain map), which includes and perceives your training partners with increasing information. Also, remember partners will not always be in your field of vision. Therefore, this exercise should teach you a heightened awareness of people outside your direct field of vision. Eventually, you should progress to full contact exercises with your partners. Always keep track of your breathing rhythm and your heart rate.
* This exercise you can also do outside of training, say in a café. Sit as central as you can with people all around you, if possible. See how many you can pick up and integrate, then try sensing their state of emotion and their movements. Can you do this simultaneously with multiple people? Does anyone stand out (not visually)? You can have a lot of fun with this training *