Contact your local CASA area office, advise them of the situation and ask for a discrete CTAF to be allocated. There are frequencies reserved for fly-ins, airshows etc. Given the discrete frequency and in particular the level of traffic, CASA would issue a NOTAM ("INCREASED TFC IN THE XXX AREA DUE FLY-IN etc.".).
Some people don't want to advertise the location of their private strip to the general public.
I know one person with an airstrip at his house where an ATO decided it was a good place to have students demonstrate precautionary searches - to his and his neighbor's displeasure.
Any significant danger of collision at an unmarked strip is with other traffic using the strip or others in the same area - not with traffic in cruise on the area frequency.