How to burn all of Debian onto BLU-RAY

Hi,
I've downloaded all 16 DVDs of 10.2, the .iso files are on my HD right now. Now what I want to do, is to burn all that data to some Blu-Ray discs that I have (I guess I'll need about 4 of them, at 25 gigs each?), NOT DVDs. How do I do this, ie. "combine" these 4.whatever gig files into ONE big 25 gig file (well, multiple ones, for the multiple Blu-Ray discs) that the Blu-Ray disc, the first one, can boot from, and from then on, can install the rest of Debian from?

Thanks.