I made a mistake on the formula field for grouping. I think you should be able to make the formula as:
{header.title} + "-" + {Itd.IRN}
or if IRN is numeric
{header.title} + "-" + totext({Itd.IRN},0,"")
If my assumptions were correct about your tables
Heading table with one row per book/IRN #
Holding table with one row per book/BIB #
ITN table with one row per book/IRN #
OND table with some where no match to ITN as never borrowed and possible multiple rows per book /itm#
then you should have a unique group header per book.
You can add a grouping below this for display purposes if you need to but I am trying to get this group to funciton for your selection criteria. If I am correct, use the summary function to do a DisctinctCount of ord.irn at this upper most formula grouping level. It will drop it in the footer but you can move it to the header. If your results are correct you can use this field for a selection criteria.
Create the paremeter as numeric.
In design view click on the distinctcount summary field. click on the selection formula. Click on the show formula. Note that the "Group Selection" should be toggled on. This is where you place summary selection items.
it will look something like:
Will this work?