Just add them - but ensure they have a different Web path
endpoint
eg - /worldmap1 and /worldmap2
[{"id":"940a9e30.7f6f1","type":"ui_worldmap","z":"3ead5d77.6a6672","group":"ab944063.3d98d","order":1,"width":6,"height":5,"name":"London","lat":"51.5","lon":"0","zoom":"12","layer":"OSM grey","cluster":"","maxage":"","usermenu":"hide","layers":"hide","panit":"false","panlock":"false","zoomlock":"false","hiderightclick":"true","coords":"none","showgrid":"false","path":"/worldmap1","x":760,"y":1600,"wires":[]},{"id":"d11b1e5.b5675e","type":"ui_worldmap","z":"3ead5d77.6a6672","group":"c3184e41.8e06f","order":1,"width":6,"height":5,"name":"Berlin","lat":"52.52","lon":"13.4","zoom":"5","layer":"Esri","cluster":"","maxage":"","usermenu":"hide","layers":"hide","panit":"false","panlock":"false","zoomlock":"false","hiderightclick":"true","coords":"none","showgrid":"false","path":"/worldmap2","x":770,"y":1680,"wires":[]},{"id":"ab944063.3d98d","type":"ui_group","z":"","name":"Group","tab":"7cb11f4b.3ee7d","order":1,"disp":true,"width":6,"collapse":false},{"id":"c3184e41.8e06f","type":"ui_group","name":"Group 2","tab":"7cb11f4b.3ee7d","order":2,"disp":true,"width":6},{"id":"7cb11f4b.3ee7d","type":"ui_tab","z":"","name":"Home","icon":"dashboard","disabled":false,"hidden":false}]