merging two workbooks where each has many worksheets

[Ghaith]

hi
im doing my accounts on excel where each work book has a lot of sheets.
And each workbook has one main sheet connects all other. My main
problem this process tougher my navigation as well as creating
duplicates where i have to insert most of the values twice which
creates duplications
my need is, i have two large workbook i want to separate the detailed
worksheets (i.e. independent workbooks) and put the main ones in on
work sheet, keep in mind to connect them to gather.
SIMPLER, first workbook has each customer details in one sheet but all
customers are listed in the main sheet where some formulas are added.
Second workbook has the sales of the customers.

regards