Let's keep it simple. If two aircraft are established on two different radials, as long as one or both of them are outside the AREA OF CONFLICT, defined by lateral separation charts that the unit should have, they are separated. It matters not whether they are inbound or outbound. I used that separation for many years, no hassles!!
As a side note, my old unit had a sliding scale for lateral separation based on angular difference between radials. The closest lat sep point was 8DME based on a 24 degree spread, if I remember correctly. As the angular difference decreased, the separation increased out to many miles.
Ready for insults!!
