Use simply linkedTo
option for linked series, where value for it is id of another series:
series: [{
data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4],
id: 'id1',
name:"object 1"
}, {
data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4],
id: 'id2',
name:"object 2"
}, {
data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4],
id: 'id3',
name:"object 3" ,
color:'#8bbc21'
}, {
data: [35, 0, 0, 0, 0, 0, 110, 0, 0, 0, 0, 70],
linkedTo: 'id3',
name:"object 3 (2)",
color:'#8bbc21'
}]