Thanks for your inquiry. Please note that Aspose.Words mimics the same behavior as MS Word does. Aspose.Words does not provide the requested feature.
However, you can use PdfSaveOptions to limit the output Pdf pages using PdfSaveOptions.PageIndex and PdfSaveOptions.PageCount properties. Please check the following code example for your kind reference.
Document doc = new Document(MyDir + "in.docx");
for(int i = 0; i < doc.getCount(); i++)
PdfSaveOptions options = new PdfSaveOptions();
doc.save(MyDir + "Out_"+ i +".pdf", options);
It might be possible that the content’s size of first page of document is 10 MB e.g there is big image at first page. So, you need to check the size of each page. In your case, I suggest you following solution.
1) Convert each page of Word document into PDF by using PdfSaveOptions.PageIndex and PdfSaveOptions.PageCount properties
2) Check the size of output Pdf files size
3) Once the size of pdf files come to the limit, stop the conversion.
4) Join the output Pdf files using Aspose.Pdf. Please check following documentation link about joining the Pdf files.