The purpose of Jamming Signal is to indicate to all other devices on the Ethernet segment that there has been a collision, and they should not send data onto the wire.
The Node detects collision during the transmission, once the collision is detected, it aborts transmitting the data.
Jamming Signals can collide but this collision will not affect the nodes because nobody is transmitting at that time.
At the point of collision, we can't send jamming signal, because the collision is not yet detected, collision is detected when the signal reaches the node and once the node sense the energy level, it sends the jamming signal.
Collision detected by the transmitting nodes send Jam signal, it's sent in all the direction, signal can't be sent towards a particular node.