Can you have space marine ultra marines and white scars in the same army?

i have just started my space marine army and i was wondering if u can have ordinary space marines and white scars in the same army list

e.g. an ultramarine tactical squad and a white scars bike squad.

thanks.Can you have space marine ultra marines and white scars in the same army?
Technically no, since they appear in separate codices. But in a friendly game, anything goes as long as your opponent agrees to it, and putting a white scars unit in a SM army is completely justifiable within the fluff, just dont expect to be able to take it to tournies