Yes. Geometric networks can contain feature classes that support Ms and feature classes that do not support Ms. However, the orphan junction feature class of the geometric network does not support Ms.
If any of the feature classes, which will participate in the geometric network, contain multipart features, M values should be set before the network is built. Once multipart features participate within a geometric network, their geometries and M values cannot be modified.
For steps on how to create a valid network feature from multipart features in a network, see ‘Repairing network topology’ in the ArcGIS Desktop Help under: Geodatabases > Editing your geodatabase.