To do that, you have to change your ‘computer’ lookup so that it gives both the computer name, and some concatenation of the names of groups in which it is a member. In doing that, you change your ‘item 5’ from a tuple of (action name, computername) into a tuple of tuples showing (actionname, (computername, computergroupnames)).
This change carries forward to where you’re retrieving the ‘td of (item)’ entries so now you need a td of (item 0 of item 1 of item 5 of it) for the computername and a td of (item 1 of item 1 of item 5 of it) for the computer groups names.
(html "<table id=resultsTable class=sortable>" & html ("<th>Issuer</th><th>Action ID</th><th>State</th><th>Baseline Name</th><th>Start Date</th><th>Name of Failed Patch</th><th>Computer Name</th><th>Computer Group</th>") &
(it) & html "</table>"
) of concatenations of trs of (
td of (item 0 of it) &
td of (item 1 of it) &
td of (item 2 of it) &
td of (item 3 of it) &
td of (item 4 of it) &
td of (item 0 of item 5 of it) &
td of (item 0 of item 1 of item 5 of it) &
td of (item 1 of item 1 of item 5 of it)
) of (
name of issuer of it,
id of it as string,
state of it,
name of it,
time issued of it as string,
((names of it, (names of it, concatenation ";" of names of bes computer groups of it) of computers of results whose
(exists statuses whose (it as string as lowercase = "failed") of it) of it) of member actions
whose (exists statuses whose (it as string as lowercase = "failed") of results of it) of it)
) of bes actions whose (
exists multiple flag of it AND
(name of it as lowercase contains "win action" as lowercase) AND
state of it is contained by "Open|Expired|Stopped"
)