Help Me to Build Query

Hello ,

I have four tables . Messages, MsgGroup,Group and UserInfo.  
Group Table Containas the name of Group.
MsgGroup  Table contains the user that are in the group.
Messages contatins the messages as per Group.
Userinformation contians the user detail.

What I want is to get last message of each group in which User is present . 

Structure of Group Table
GID      Name
1             Good
2              Bad
3             Interesting

Structure of MsgGroup Is
MID      UserID            GID      
1   &n ...