  The Halpha emission of a set of southern gamma-Cas stars was monitored since
2019, with the aim of detecting transition events and examining how their
peculiar X-ray emission would react in such cases. Two stars, HD119682 and
V767Cen, were found to display slowly decreasing disk emissions. These
decreases were not perfectly monotonic and several temporary and limited
re-building events were observed. For HD119682, the emission component in
Halpha disappeared in mid-July 2020. In X-rays, the X-ray flux was twice
smaller than recorded two decades ago but of a similar level as observed a
decade ago. The X-ray flux decreased over the campaign by 30%, but the hardness
remained similar in datasets of all epochs. In particular, the gamma-Cas
character remained as clear as before even when there was no trace of disk
emission in the Halpha line. For V767Cen, the full disappearance of disk
emission in Halpha never occurred. We followed closely a disk rebuilding event,
but no significant change in flux or hardness was detected. These behaviours
are compared to those of other gamma-Cas stars and their consequences on the
X-ray generation are discussed.
