Lets say I have two groups which share a set of elements & nodes. Now I want to delete the common elements & nodes from one of the groups only (the other one should retain the said elements & nodes). How do I go about doing the above in Femap? I was not able to find any Group editing commands in Femap.
Is deleting & recreating one of group the only option?
Not exactly "editing", but there are 2 ways I can think of to accomplish what you want.
1) Activate the group where you do not want to retain nodes & elements. Then simply go to Group->Element->ID, set the Add/Remove/Exclude option to Exclude and choose the other Group from the drop-down. You will then have to do the same for Group->Node->ID. Clearly this takes multiple steps and if your groups are more complicated this probably isn't all that practical.
2) Use Group->Operations->Booleans. Here there are a number of options to Add, Subtract and otherwise manipulate groups. The only downfall with this approach is that it creates a new group rather than updating the original.