How do I get all genes that overlap a peak as a comma separated column within a single row for the peak?

I tried ChIPseeker:

annotatePeak(peaks, level = "gene", 
                         addFlankGeneInfo = FALSE,
                         assignGenomicAnnotation = TRUE,
                         TxDb = TxDb.Mmusculus.UCSC.mm10.knownGene, 
                         annoDb = "org.Mm.eg.db",
                         ignoreOverlap = FALSE,
                         overlap="all")

Result: 

Doesn't report all genes within peak. If change addFlankGeneInfo = TRUE, get some of the genes but doesn't cover exact peak size so not useful in this case.

I tried ChIPpeakAnno:

ucsc.mm10.knownGene <- genes(TxDb.Mmusculus.UCSC.mm10.knownGene)
gr_peaks <- toGRanges(merge_peaks, format="BED", header = FALSE, feature = "gene")
peaks_anno <- annotatePeakInBatch(gr_peaks, 
                                        AnnotationData = ucsc.mm10.knownGene,
                                        output = "both",
                                        select = "all")
peaks_anno <- addGeneIDs(annotatedPeak = peaks_anno,
                              orgAnn = "org.Mm.eg.db",
                              feature_id_type = "entrez_id",
                              IDs2Add = "symbol")

Result:

Returns all genes in peaks but in new rows instead of list in one column.

seqnames start end width strand feature start_position end_position feature_strand insideFeature distancetoFeature shortestDistance fromOverlappingOrNearest symbol

X07696.103889 chr11 96268247 96356723 88477 X07696 103889 96351632 96354014 + includeFeature -83385 2709 NearestLocation Hoxb2

X07696.15410 chr11 96268247 96356723 88477 X07696 15410 96323126 96347930 + includeFeature -54879 8793 NearestLocation Hoxb3

X07696.15412 chr11 96268247 96356723 88477 X07696 15412 96318267 96321638 + includeFeature -50020 35085 NearestLocation Hoxb4

X07696.15413 chr11 96268247 96356723 88477 X07696 15413 96303512 96306121 + includeFeature -35265 35265 NearestLocation Hoxb5

X07696.15414 chr11 96268247 96356723 88477 X07696 15414 96299171 96301569 + includeFeature -30924 30924 NearestLocation Hoxb6

X07696.15415 chr11 96268247 96356723 88477 X07696 15415 96286646 96290163 + includeFeature -18399 18399 NearestLocation Hoxb7

X07696.15416 chr11 96268247 96356723 88477 X07696 15416 96281905 96285325 + includeFeature -13658 13658 NearestLocation Hoxb8

X07696.15417 chr11 96268247 96356723 88477 X07696 15417 96271330 96276593 + includeFeature -3083 3083 NearestLocation Hoxb9

Want something like:

seqnames start end width strand feature start_position end_position feature_strand insideFeature distancetoFeature shortestDistance fromOverlappingOrNearest symbol

X07696.103889 chr11 96268247 96356723 88477 X07696 103889 96351632 96354014 + includeFeature -83385 2709 NearestLocation Hoxb2, Hoxb3, Hoxb4, Hoxb5, Hoxb6, Hoxb7, Hoxb8, Hoxb9