\placefigure{some title}
{\placeontopofeachother
{\externalfigure[figure 1]}
{\externalfigure[figure 2]}}

\placefigure{some title}
{\hbox\placesidebyside
{\externalfigure[figure 1]}
{\externalfigure[figure 2]}}

Wolfgang

and:

\placefigure
[here,force][fig:Ex6]{Ux zeuhl, ma lamax quolt epp ik, korsa ozlint
vusp urfa,.}
\startcombination[2*1]
{\externalfigure[Ex6a]}{}
{\externalfigure[Ex6b]}{}
^^
\stopcombination

Wolfgang

Both work. Thank you. Stupid of me to forget or neglect a pair of empty curly braces.