Yes, you do need a bit of JavaScript to accomplish this!
The HTML inside the <body> first sets up two <div> element for the two animations, and then defines two "instances" of HAniS for the animations, followed by the JavaScript functions needed to connect the two animations::
<div id="handiv" style="display:inline-block;width:500px;"> </div> <div id="handiv22" style="display:inline-block;width:500px;"> </div> <script> var b = new HAniSF(); var a = new HAniSF(); function aready() { a.frameChanged(changb); } function changb(frm) { b.showFrame(frm); } function init() { a.setup('hanist1.txt','handiv', aready ) b.setup('filenames = TIR1.GIF, TIR2.GIF, TIR3.GIF \n imagecan_style=border-radius:30px; \n start_looping=false \n' + 'overlay_nonewdiv=t \n overlay_filenames=TMAP.GIF \n controls = zoom, overlay \n' + ' overlay_labels=Map \n buttons_style = flex:auto;margin:2px;' , 'handiv22'); } window.onload = init(); </script>(Note also in the 2nd instance, the overlay_filename need only be given once, since it applies to all frames.)