Please make the Asciiv3 format easier to read by grouping decay products

In the AsciiHepMC2 format, the decay products are grouped and can be easily found when reading the file.

In the Asciiv3 format, the decay products can be separated by many particles from other decays.

The following examples show the same decay from the the same event in AsciiHepMC2 and Asciiv3 format. Both examples were created with HepMC 3.2.3.

AsciiHepMC2 decay with grouped decay products:

P 10014 21 3.0475622025960547e-14 -1.4960255256823984e-14 -5.4950461969738093e+01 5.4950461969738086e+01 0.0000000000000000e+00 41 0 0 -11 2 1 103 2 108
...
V -11 0 0 0 0 0 0 2 0
P 10018 21 2.1660451210436804e-13 -9.4146912488213275e-14 -4.9784554224732538e+01 4.9784554224732517e+01 0.0000000000000000e+00 42 0 0 -12 2 1 103 2 102
P 10019 21 8.7047004749495216e-01 -4.2676088055794892e-01 -5.0974673471196814e+00 5.1888357372065474e+00 0.0000000000000000e+00 43 0 0 -64 2 1 102 2 108

Asciiv3 decay with two particles from the same decay separated by more than 60 lines:

P 14 7 21 3.0475622025960547e-14 -1.4960255256823984e-14 -5.4950461969738093e+01 5.4950461969738086e+01 0.0000000000000000e+00 41
...
P 18 14 21 2.1660451210436804e-13 -9.4146912488213275e-14 -4.9784554224732538e+01 4.9784554224732517e+01 0.0000000000000000e+00 42
...
P 84 14 21 8.7047004749495216e-01 -4.2676088055794892e-01 -5.0974673471196814e+00 5.1888357372065474e+00 0.0000000000000000e+00 43