Complex sentence: The SNP, although being predominantly social-democratic, joined the European Progressive Democrats, a conservative group led by the French Gaullist Rally for the Republic, the VU and the FDF the heterogeneous Technical Group of Independents and the SVP the European People's Party.
Split into simpler sentences: The SNP, although being predominantly social-democratic, joined the European Progressive Democrats, a conservative group led by the French Gaullist Rally for the Republic. The VU and the FDF joined the heterogeneous Technical Group of Independents, while the SVP joined the European People's Party.