slide show frame elements (?)

[Gennady]

Hello, All.
In one of my stp project i have bunch of vertical beams overlapping
each other in groups like:
0----->
0-----x---->
0-----x----x----->
(all three beams start from the same point 0). And I'm guessing it
could be separate slides for time ordered sequence of frame assembly.
But assembly_sequence_number attribute for all
assembly_design_structural_member is zero.
Is there other way to group members by time frames?

Thanks in advance.