Professional Mastering, Gapless CDs and Markers?

[chumbox]

Hey All

Have searched around but cannot seem to find the answer I am looking for.

I have 6 tracks (for an EP) which are all mixed down and about to be mastered. All the songs are done in a way that when the CD is pressed I would like it to be gapless so it is one continuous album.

Now I am going to send it off for mastering but wasn't sure if I need all these files in one session and if I have to mark them myself, or will they be able to do the marking and gapless editing required at the mastering studio?

All the tracks are written and recorded so they can easily run into each other, they are just currently in 6 different files.

Thanks