Print for GR slip collectively

Guys, i want to make printout directly after i make GR in MIGO, and i want it printout collectively, not print by item.

I have customizing in MN21, and choose '3' in MIGO, but it still printout one by one, for in the same document i have 3 items, it printout 3 pages sperately.

How can i print these 3 items together in the same page?