It is not uncommon for a brand to identify more than one actual or potential competitive frame of reference, if competition widens or the firm plans to expand into new categories.
There are two main options with multiple frames of reference. One is to first develop the best possible positioning for each type or class of competitors and then create one combined positioning robust enough to effectively address all. If competition is too diverse, however, it may be necessary to prioritize competitors and choose the most important set as the competitive frame.
Try not to be all things to all people—that leads to lowest-common-denominator positioning, which is typically ineffective.