This part is subjective..

I would suggest normal Canon & Nikon to use between f4.5 to f5.6 for group shots.

While FF camera need around f8 to get the DoF

But if you got yourselve the not so popular Olympus dSLR that come with extra-DoF technology (I was told all Olympus SLR has this advanced feature), you only need f2.8 to get the DoF. It basically mean you can almost always use wide open for all shots...

But be carefull... Althought the Olympus has extra DoF... its autofocus is not reliable in less ideal room light. In that case, I would suggest simply manual focus... No need to view throught the small view finder... agak-agak will do... Remember to take advantage of its high-tech extra-DoF that no other dSLR has...

Now... Who said Olympus is a funny brand?

Seems there are 3 presentable gals out of 5... Really good!

Any closeup of the beauties?

The second from left seems really cun...